Initial commit

2026-02-26 17:13:24 +00:00 · 2019-06-26 22:36:14 -05:00
commit 37813a2727
39 changed files with 16406 additions and 0 deletions
--- a/13
+++ b/13
@@ -0,0 +1,13 @@
+Copyright (c) 2019, Andrew Kay
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
--- a/README.md
+++ b/README.md
@@ -0,0 +1,14 @@
+# coax-interface
+
+> Hello mainframe!
+
+coax-interface is a set of tools for interfacing with [IBM 3270](https://en.wikipedia.org/wiki/IBM_3270) type terminals.
+
+## Contents
+
+* [pycoax](pycoax) - Python IBM 3270 coaxial interface library
+* [interface1](interface1) - A serial attached Arduino interface using the National Semiconductor DP8340 and DP8341
+
+## See Also
+
+* [oec](https://github.com/lowobservable/oec) - An open replacement for the IBM 3174 Establishment Controller
--- a/interface1/README.md
+++ b/interface1/README.md
@@ -0,0 +1,32 @@
+# interface1
+
+A serial attached Arduino interface using the National Semiconductor DP8340 and DP8341.
+
+## Schematic
+
+![Schematic](hardware/schematic.svg)
+
+## Materials
+
+This interface requires an [Arduino Mega](https://store.arduino.cc/usa/mega-2560-r3).
+
+ Item | Quantity | Description                   | Reference | Part Number                   | Source
+:----:|---------:|-------------------------------|-----------|-------------------------------|----------------
+1     | 1        | IBM 3270 Protocol Transmitter | U1        | National Semiconductor DP8340 | eBay - Obsolete
+2     | 1        | IBM 3270 Protocol Receiver    | U2        | National Semiconductor DP8341 | eBay - Obsolete
+3     | 1        | Quad RS-422 Line Driver       | U3        | Texas Instruments DS3487      | eBay - Obsolete
+4     | 1        | Pulse Transformer - 1:1:1     | T1        | Pulse PE-5762                 | eBay - Obsolete
+5     | 1        | Crystal - 18.867 MHz          | Y1        | IQD LFXTAL057125 *            | [Mouser](https://www.mouser.com/ProductDetail/IQD/LFXTAL057125Bulk?qs=%2Fha2pyFaduieSzBxw7UAJRZlCXjBZuIKPyofrMyYW7wVunrhuBMeiQd4MCF50LLz)
+6     | 2        | Resistor - 33 ohm             | R2, R4    |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-33-RC?qs=sGAEpiMZZMu61qfTUdNhGzoeXLT9qgk%252BV159XfY8c4Q%3D)
+7     | 1        | Resistor - 120 ohm            | R6        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-120-RC?qs=sGAEpiMZZMu61qfTUdNhG7Of23Pr6gu8rRE5UXBJoDw%3D)
+8     | 2        | Resistor - 150 ohm            | R1, R5    |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-150-RC?qs=sGAEpiMZZMu61qfTUdNhG2ZzrN2CiS9nBcPQNrtAXYk%3D)
+9     | 1        | Resistor - 500 ohm            | R7        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-499-RC?qs=sGAEpiMZZMu61qfTUdNhG6lpw21m8SOsvE2iEnaSg1s%3D)
+10    | 1        | Resistor - 510 ohm            | R3        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-510-RC?qs=sGAEpiMZZMu61qfTUdNhG9RrhBeDi8B8FBVTnOgGHiw%3D)
+11    | 1        | Capacitor - 30pF              | C1        |                               | [Mouser](https://www.mouser.com/ProductDetail/Vishay-Cera-Mite/561R10TCCQ30?qs=sGAEpiMZZMt1mVBmZSXTPNbSVgF1iSv4q4pBhPBLwuM%3D)
+12    | 1        | Coax Connector                | J1        |                               |
+
+\* - SMD
+
+## Firmware
+
+The firmware currently provides the ability to send commands and receive responses - it is designed to be used to implement a terminal controller, not to emulate a terminal.
--- a/interface1/firmware/CoaxTransceiver.cpp
+++ b/interface1/firmware/CoaxTransceiver.cpp
@@ -0,0 +1,305 @@
+// Copyright (c) 2019, Andrew Kay
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include <Arduino.h>
+
+#include "CoaxTransceiver.h"
+           
+// Arduino Mega pins...
+//
+//  Arduino   Arduino Port        Label        DP8340N   DP8341N 
+//    Pin       and Mask                         Pin       Pin
+// ---------|--------------|-----------------|---------|---------
+//    36    |   PC1        | D2              |   10    |   14
+//    37    |   PC0        | D3              |    9    |   15
+//    29    |   PA7        | D4              |    8    |   16
+//    28    |   PA6        | D5              |    7    |   17
+//    27    |   PA5        | D6              |    6    |   18
+//    26    |   PA4        | D7              |    5    |   19
+//    25    |   PA3        | D8              |    4    |   20
+//    24    |   PA2        | D9              |    3    |   21
+//    23    |   PA1        | D10             |    2    |   22
+//    22    |   PA0        | D11             |    1    |   23
+// --------- -------------- ----------------- --------- ---------
+//     8    |   PH5 0x20   | REGISTER LOAD   |   23    |
+//     9    |   PH6 0x40   | REGISTERS FULL  |   22    |
+//    10    |              | AUTO RESPONSE   |   21    |
+//    11    |              | EVEN/ODD PARITY |   18    |
+//    12    |   PB6 0x40   | PARITY CONTROL  |   19    |
+// --------- -------------- ----------------- --------- ---------
+//    18*   |   PD3 0x08   | RECEIVER ACTIVE |         |    7
+//     2    |   PE4 0x10   | DATA AVAILABLE  |         |   10
+//     3    |   PE5 0x20   | ERROR           |         |    8
+//     4    |              | DATA CONTROL    |         |    5
+//     5    |   PE3 0x08   | REGISTER READ   |         |    9
+//     6    |   PH3 0x08   | OUTPUT CONTROL  |         |   11
+//     7    |   PH4 0x10   | OUTPUT ENABLE   |         |   13
+//
+// * - Interrupt capable pin
+
+#define TX_REGISTER_LOAD_PIN 8
+#define TX_REGISTERS_FULL_PIN 9
+#define TX_AUTO_RESPONSE_PIN 10
+#define TX_EVEN_ODD_PARITY_PIN 11
+#define TX_PARITY_CONTROL_PIN 12
+
+#define RX_ACTIVE_PIN 18
+#define RX_DATA_AVAILABLE_PIN 2
+#define RX_ERROR_PIN 3
+#define RX_DATA_CONTROL_PIN 4
+#define RX_REGISTER_READ_PIN 5
+#define RX_OUTPUT_CONTROL_PIN 6
+#define RX_OUTPUT_ENABLE_PIN 7
+
+#define RX_STATE_DISABLED 0
+#define RX_STATE_WAITING 1
+#define RX_STATE_RECEIVING 2
+#define RX_STATE_RECEIVED 3
+
+static volatile uint8_t CoaxTransceiver::rxState;
+static volatile uint16_t *CoaxTransceiver::rxBuffer;
+static volatile size_t CoaxTransceiver::rxBufferSize;
+static volatile int /* ssize_t */ CoaxTransceiver::rxBufferCount;
+
+#define NOP __asm__("nop\n\t")
+
+static void CoaxTransceiver::setup() {
+  // Configure data bus.
+  dataBusSetup();
+
+  // Configure receiver (DP8341N).
+  rxSetup();
+
+  // Configure transmitter (DP8340N).
+  txSetup();
+}
+
+static int /* ssize_t */ CoaxTransceiver::transmitReceive(uint16_t commandWord, uint8_t *dataBuffer, size_t dataBufferCount, uint16_t *receiveBuffer, size_t receiveBufferSize, uint16_t timeout) {
+  int returnValue = transmit(commandWord, dataBuffer, dataBufferCount);
+
+  if (returnValue < 0) {
+    return returnValue;
+  }
+
+  return receive(receiveBuffer, receiveBufferSize, timeout);
+}
+
+static void CoaxTransceiver::dataBusSetup() {
+  DDRA = B00000000;
+  DDRC = B00000000;
+}
+
+static void CoaxTransceiver::rxSetup() {
+  // Data Control - Amplifier Inputs
+  pinMode(RX_DATA_CONTROL_PIN, OUTPUT);
+  
+  digitalWrite(RX_DATA_CONTROL_PIN, HIGH);
+
+  // Register Read
+  pinMode(RX_REGISTER_READ_PIN, OUTPUT);
+
+  digitalWrite(RX_REGISTER_READ_PIN, HIGH);
+
+  // Output Control - Data
+  pinMode(RX_OUTPUT_CONTROL_PIN, OUTPUT);
+
+  digitalWrite(RX_OUTPUT_CONTROL_PIN, HIGH);
+
+  // Output Enable - Active
+  pinMode(RX_OUTPUT_ENABLE_PIN, OUTPUT);
+
+  digitalWrite(RX_OUTPUT_ENABLE_PIN, HIGH);
+
+  // Receiver Active
+  pinMode(RX_ACTIVE_PIN, INPUT);
+
+  attachInterrupt(digitalPinToInterrupt(RX_ACTIVE_PIN), rxActiveInterrupt, RISING);
+
+  // Data Available
+  pinMode(RX_DATA_AVAILABLE_PIN, INPUT);
+
+  // Error
+  pinMode(RX_ERROR_PIN, INPUT); 
+}
+
+static void CoaxTransceiver::txSetup() {
+  // Register Load
+  pinMode(TX_REGISTER_LOAD_PIN, OUTPUT);
+
+  digitalWrite(TX_REGISTER_LOAD_PIN, HIGH);
+  
+  // Auto Response - Data
+  pinMode(TX_AUTO_RESPONSE_PIN, OUTPUT);
+
+  digitalWrite(TX_AUTO_RESPONSE_PIN, HIGH);
+  
+  // Even/Odd Parity - Even
+  pinMode(TX_EVEN_ODD_PARITY_PIN, OUTPUT);
+
+  digitalWrite(TX_EVEN_ODD_PARITY_PIN, HIGH);
+
+  // Parity Control - Data
+  pinMode(TX_PARITY_CONTROL_PIN, OUTPUT);
+
+  digitalWrite(TX_PARITY_CONTROL_PIN, HIGH);
+
+  // Registers Full
+  pinMode(TX_REGISTERS_FULL_PIN, INPUT);
+}
+
+static int /* ssize_t */ CoaxTransceiver::transmit(uint16_t commandWord, uint8_t *dataBuffer, size_t dataCount) {
+  // Ensure receiver is inactive.
+  if (rxState != RX_STATE_DISABLED) {
+    return ERROR_TX_RECEIVER_ACTIVE;
+  }
+  
+  if ((PIND & 0x8) == 0x8) {
+    return ERROR_TX_RECEIVER_ACTIVE;
+  }
+
+  // Disable interrupts.
+  noInterrupts();
+
+  // Disable receiver output.
+  PORTH &= ~0x10; // RX Output Enable - Low (Disable)
+
+  // Configure data bus for output.
+  DDRA = B11111111;
+  DDRC = B00000011;
+
+  // Send command word - we make an assumption here that TX_REGISTERS_FULL is not set.
+  PORTC = (PINC & 0xfc) | ((commandWord >> 8) & 0x3);
+  PORTA = commandWord & 0xff;
+
+  PORTH &= ~0x20; // TX Register Load - Low (Load)
+  PORTH |=  0x20; // TX Register Load - High
+
+  // Send data - offload parity computation to DP8340.
+  if (dataCount > 0) {
+    // Enable transmitter parity calculation.
+    PORTB &= ~0x40; // TX Parity Control - Low
+    
+    for (int index = 0; index < dataCount; index++) {
+      // Wait while TX Registers Full is high.
+      while ((PINH & 0x40) == 0x40) {
+        NOP;
+      }
+      
+      uint8_t data = dataBuffer[index];
+
+      PORTC = (PINC & 0xfc) | ((data >> 6) & 0x3);
+      PORTA = (data << 2);
+
+      PORTH &= ~0x20; // TX Register Load - Low (Load)
+      PORTH |=  0x20; // TX Register Load - High
+    }
+
+    // Disable transmitter parity calculation.
+    PORTB |= 0x40; // TX Parity Control - High
+  }
+
+  // Configure data bus for input.
+  DDRA = B00000000;
+  DDRC = B00000000;
+
+  // Enable receiver output.
+  PORTH |= 0x10; // RX Output Enable - High (Enable)
+
+  // Enable interrupts.
+  interrupts();
+
+  return dataCount;
+}
+
+static int /* ssize_t */ CoaxTransceiver::receive(uint16_t *buffer, size_t bufferSize, uint16_t timeout) {
+  rxBuffer = buffer;
+  rxBufferSize = bufferSize;
+
+  rxState = RX_STATE_WAITING;
+  
+  if (timeout > 0) {
+    unsigned long startTime = millis();
+    
+    while (rxState == RX_STATE_WAITING) {
+      // https://www.forward.com.au/pfod/ArduinoProgramming/TimingDelaysInArduino.html#unsigned
+      if ((millis() - startTime) > timeout) {
+        rxState = RX_STATE_DISABLED;
+        return ERROR_RX_TIMEOUT;
+      }
+    }
+  }
+  
+  while (rxState != RX_STATE_RECEIVED) {
+    NOP;
+  }
+
+  rxState = RX_STATE_DISABLED;
+
+  return rxBufferCount;
+}
+
+static void CoaxTransceiver::rxActiveInterrupt() {
+  uint16_t data;
+  uint8_t mask;
+  
+  if (rxState == RX_STATE_DISABLED) {
+    return;
+  }
+
+  rxState = RX_STATE_RECEIVING;
+
+  rxBufferCount = 0;
+
+  do {
+    while ((PINE & 0x30) == 0) {
+      NOP;
+    }
+    
+    if (/* ERROR */ (PINE & 0x20) == 0x20) {
+      mask = 0x20;
+            
+      PORTH &= ~0x8; // Output Control - Low (Error)
+      PORTE &= ~0x8; // Register Read - Low
+
+      // Read and mark as error.
+      data = (((PINC & 0x3) | 0x80) << 8) | PINA;
+
+      PORTE |= 0x8; // Register Read - High
+      PORTH |= 0x8; // Output Control - High (Data)
+    } else if (/* DATA AVAILABLE */ (PINE & 0x10) == 0x10) {
+      mask = 0x10;
+      
+      PORTE &= ~0x8; // Register Read - Low
+
+      // Read.
+      data = ((PINC & 0x3) << 8) | PINA;
+     
+      PORTE |= 0x8; // Register Read - High
+    }
+    
+    if (rxBufferCount >= rxBufferSize) {
+      rxBufferCount = ERROR_RX_OVERFLOW;
+      goto EXIT;
+    }
+    
+    rxBuffer[rxBufferCount++] = data;
+
+    while ((PINE & mask) == mask) {
+      NOP;
+    }
+  } while ((PIND & 0x8) == 0x8);
+
+EXIT:
+  rxState = RX_STATE_RECEIVED;
+}
--- a/interface1/firmware/CoaxTransceiver.h
+++ b/interface1/firmware/CoaxTransceiver.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2019, Andrew Kay
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#pragma once
+
+#include <Arduino.h>
+
+#define ERROR_TX_RECEIVER_ACTIVE -1
+#define ERROR_RX_TIMEOUT -2
+#define ERROR_RX_OVERFLOW -3
+
+class CoaxTransceiver {
+  public:
+    static void setup();
+    static int /* ssize_t */ transmitReceive(uint16_t commandWord, uint8_t *dataBuffer, size_t dataBufferCount, uint16_t *receiveBuffer, size_t receiveBufferSize, uint16_t timeout);
+  
+  private:
+    static void dataBusSetup();
+    static void rxSetup();
+    static void txSetup();
+    static int /* ssize_t */ transmit(uint16_t commandWord, uint8_t *dataBuffer, size_t dataCount);
+    static int /* ssize_t */ receive(uint16_t *buffer, size_t bufferSize, uint16_t timeout);
+    static void rxActiveInterrupt();
+
+    static volatile uint8_t rxState;
+    static volatile uint16_t *rxBuffer;
+    static volatile size_t rxBufferSize;
+    static volatile int /* ssize_t */ rxBufferCount;
+};
--- a/interface1/firmware/firmware.ino
+++ b/interface1/firmware/firmware.ino
@@ -0,0 +1,304 @@
+// Copyright (c) 2019, Andrew Kay
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#include <Arduino.h>
+
+#include "CoaxTransceiver.h"
+
+#define COMMAND_RESET 0x01
+#define COMMAND_EXECUTE 0x02
+#define COMMAND_EXECUTE_OFFLOAD 0x03
+
+#define ERROR_INVALID_MESSAGE 1
+#define ERROR_UNKNOWN_COMMAND 2
+#define ERROR_UNKNOWN_OFFLOAD_COMMAND 3
+
+#define UNPACK_DATA_WORD(w) (uint8_t) ((w >> 2) & 0xff)
+
+void handleResetCommand(uint8_t *buffer, int bufferCount) {
+  uint8_t response[] = { 0x01, 0x00, 0x00, 0x01 };
+  
+  sendMessage(response, 4);
+}
+
+void handleExecuteCommand(uint8_t *buffer, int bufferCount) {
+  if (bufferCount < 6) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+  
+  uint16_t commandWord = (buffer[0] << 8) | buffer[1];
+  uint16_t receiveCount = (buffer[2] << 8) | buffer[3];
+  uint16_t timeout = (buffer[4] << 8) | buffer[5];
+
+  uint8_t *dataBuffer = buffer + 6;
+  uint16_t dataBufferCount = bufferCount - 6;
+
+  uint16_t *receiveBuffer = (uint16_t *) (buffer + 2);
+  
+  bufferCount = CoaxTransceiver::transmitReceive(commandWord, dataBuffer, dataBufferCount, receiveBuffer, receiveCount, timeout);
+
+  if (bufferCount < 0) {
+    sendErrorMessage(100 + ((-1) * bufferCount));
+    return;
+  }
+
+  // Send the response message.
+  buffer[1] = 0x01;
+  
+  bufferCount = 1 + (bufferCount * 2);
+
+  sendMessage(buffer + 1, bufferCount);
+}
+
+void handleExecuteOffloadCommand(uint8_t *buffer, int bufferCount) {
+  if (bufferCount < 1) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  uint8_t command = buffer[0];
+
+  if (command == 0x01) {
+    handleOffloadLoadAddressCounter(buffer + 1, bufferCount - 1);
+  } else if (command == 0x02) {
+    handleOffloadWrite(buffer + 1, bufferCount - 1);
+  } else {
+    sendErrorMessage(ERROR_UNKNOWN_OFFLOAD_COMMAND);
+  }
+}
+
+void handleOffloadLoadAddressCounter(uint8_t *buffer, int bufferCount) {
+  uint16_t response;
+  
+  if (bufferCount < 2) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  uint8_t hi = buffer[0];
+  uint8_t lo = buffer[1];
+  
+  // TODO: error handling...
+  CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_HI */ 0x11, &hi, 1, &response, 1, 0);
+  CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_LO */ 0x51, &lo, 1, &response, 1, 0);
+
+  // Send the response message.
+  uint8_t message[] = { 0x01 };
+  
+  sendMessage(message, 1);
+}
+
+void handleOffloadWrite(uint8_t *buffer, int bufferCount) {
+  uint16_t response;
+  
+  if (bufferCount < 5) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  uint8_t addressHi = buffer[0];
+  uint8_t addressLo = buffer[1];
+  bool restoreOriginalAddress = buffer[2];
+  uint16_t repeatCount = (buffer[3] << 8) | buffer[4];
+
+  uint8_t *dataBuffer = buffer + 5;
+  uint16_t dataBufferCount = bufferCount - 5;
+  
+  if (dataBufferCount < 1) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  // Repeat the provided data if applicable.
+  if (repeatCount > 0) {
+    uint16_t dataBufferIndex = dataBufferCount;
+
+    for (int repeatIndex = 0; repeatIndex < repeatCount; repeatIndex++) {
+      for (int index = 0; index < dataBufferCount; index++) {
+        dataBuffer[dataBufferIndex++] = dataBuffer[index];
+      }
+    }
+
+    dataBufferCount *= (repeatCount + 1);
+  }
+  
+  // Store original address if applicable.
+  uint8_t originalAddressHi;
+  uint8_t originalAddressLo;
+
+  if (restoreOriginalAddress) {
+    CoaxTransceiver::transmitReceive(/* READ_ADDRESS_COUNTER_HI */ 0x15, NULL, 0, &response, 1, 0);
+
+    originalAddressHi = UNPACK_DATA_WORD(response);
+
+    CoaxTransceiver::transmitReceive(/* READ_ADDRESS_COUNTER_LO */ 0x55, NULL, 0, &response, 1, 0);
+    
+    originalAddressLo = UNPACK_DATA_WORD(response);
+  }
+
+  // Move to start address if applicable.
+  if (!(addressHi == 0xff && addressLo == 0xff)) {
+    CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_HI */ 0x11, &addressHi, 1, &response, 1, 0);
+    CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_LO */ 0x51, &addressLo, 1, &response, 1, 0);
+  }
+
+  // Write buffer.
+  CoaxTransceiver::transmitReceive(/* WRITE_DATA */ 0x31, dataBuffer, dataBufferCount, &response, 1, 0);
+
+  // Restore original address if applicable.
+  if (restoreOriginalAddress) {
+    CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_HI */ 0x11, &originalAddressHi, 1, &response, 1, 0);
+    CoaxTransceiver::transmitReceive(/* LOAD_ADDRESS_COUNTER_LO */ 0x51, &originalAddressLo, 1, &response, 1, 0);
+  }
+
+  // Send the response message.
+  uint8_t message[] = { 0x01 };
+  
+  sendMessage(message, 1);
+}
+
+void handleMessage(uint8_t *buffer, int bufferCount) {
+  if (bufferCount < 1) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  uint8_t command = buffer[0];
+
+  if (command == COMMAND_RESET) {
+    handleResetCommand(buffer + 1, bufferCount - 1);
+  } else if (command == COMMAND_EXECUTE) {
+    handleExecuteCommand(buffer + 1, bufferCount - 1);
+  } else if (command == COMMAND_EXECUTE_OFFLOAD) {
+    handleExecuteOffloadCommand(buffer + 1, bufferCount - 1);
+  } else {
+    sendErrorMessage(ERROR_UNKNOWN_COMMAND);
+  }
+}
+
+#define FRAME_END 0xc0
+#define FRAME_ESCAPE 0xdb
+#define FRAME_ESCAPE_END 0xdc
+#define FRAME_ESCAPE_ESCAPE 0xdd
+
+enum {
+  WAIT_START,
+  DATA,
+  ESCAPE
+} frameState;
+
+#define FRAME_BUFFER_SIZE (25 * 80) + 32
+
+uint8_t frameBuffer[FRAME_BUFFER_SIZE];
+int frameBufferCount = 0;
+
+void handleFrame(uint8_t *buffer, int bufferCount) {
+  if (bufferCount < 4) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  int count = (buffer[0] << 8) | buffer[1];
+
+  if (bufferCount - 4 != count) {
+    sendErrorMessage(ERROR_INVALID_MESSAGE);
+    return;
+  }
+
+  handleMessage(buffer + 2, count);
+}
+
+void sendMessage(uint8_t *buffer, int bufferCount) {
+  Serial.write((char) FRAME_END);
+
+  // Write the length.
+  Serial.write((char) bufferCount >> 8);
+  Serial.write((char) bufferCount);
+
+  for (int index = 0; index < bufferCount; index++) {
+    if (buffer[index] == FRAME_END) {
+      Serial.write((char) FRAME_ESCAPE);
+      Serial.write((char) FRAME_ESCAPE_END);
+    } else if (buffer[index] == FRAME_ESCAPE) {
+      Serial.write((char) FRAME_ESCAPE);
+      Serial.write((char) FRAME_ESCAPE_ESCAPE);
+    } else {
+      Serial.write((char) buffer[index]);
+    }
+  }
+
+  // Write the placeholder for checksum.
+  Serial.write((char) 0x00);
+  Serial.write((char) 0x00);
+  
+  Serial.write((char) FRAME_END);
+
+  Serial.flush();
+}
+
+void sendErrorMessage(uint8_t code) {
+  uint8_t message[] = { 0x02, code };
+  
+  sendMessage(message, 2);
+}
+
+void setup() {
+  // Configure serial port and state machine.
+  Serial.begin(115200);
+
+  frameState = WAIT_START;
+
+  while (Serial.available() > 0) {
+    Serial.read();
+  }
+  
+  // Configure the transceiver.
+  CoaxTransceiver::setup();
+}
+
+void loop() {
+  if (Serial.available() > 0) {
+    uint8_t byte = Serial.read();
+
+    if (frameState == WAIT_START) {
+      if (byte == FRAME_END) {
+        frameState = DATA;
+      }
+    } else if (frameState == DATA) {
+      if (byte == FRAME_END) {
+        if (frameBufferCount > 0) {
+          handleFrame(frameBuffer, frameBufferCount);
+        }
+
+        frameBufferCount = 0;
+      } else if (byte == FRAME_ESCAPE) {
+        frameState = ESCAPE;
+      } else {
+        // TODO: overflow...
+        frameBuffer[frameBufferCount++] = byte;
+      }
+    } else if (frameState == ESCAPE) {
+      if (byte == FRAME_ESCAPE_END) {
+        // TODO: overflow...
+        frameBuffer[frameBufferCount++] = FRAME_END;
+      } else if (byte == FRAME_ESCAPE_ESCAPE) {
+        // TODO: overflow...
+        frameBuffer[frameBufferCount++] = FRAME_ESCAPE;
+      }
+
+      frameState = DATA;
+    }
+  }
+}
--- a/interface1/hardware/hardware-cache.lib
+++ b/interface1/hardware/hardware-cache.lib
@@ -0,0 +1,256 @@
+EESchema-LIBRARY Version 2.4
+#encoding utf-8
+#
+# Connector_Conn_Coaxial
+#
+DEF Connector_Conn_Coaxial J 0 40 Y N 1 F N
+F0 "J" 10 120 50 H V C CNN
+F1 "Connector_Conn_Coaxial" 115 0 50 V V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ *BNC*
+ *SMA*
+ *SMB*
+ *SMC*
+ *Cinch*
+$ENDFPLIST
+DRAW
+A -2 0 71 1636 0 0 1 10 N -70 20 70 0
+A -1 0 71 0 -1638 0 1 10 N 70 0 -70 -20
+C 0 0 20 0 1 8 N
+P 2 0 1 0 -100 0 -20 0 N
+P 2 0 1 0 0 -100 0 -70 N
+X In 1 -200 0 100 R 50 50 1 1 P
+X Ext 2 0 -200 100 U 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+# Device_C
+#
+DEF Device_C C 0 10 N Y 1 F N
+F0 "C" 25 100 50 H V L CNN
+F1 "Device_C" 25 -100 50 H V L CNN
+F2 "" 38 -150 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ C_*
+$ENDFPLIST
+DRAW
+P 2 0 1 20 -80 -30 80 -30 N
+P 2 0 1 20 -80 30 80 30 N
+X ~ 1 0 150 110 D 50 50 1 1 P
+X ~ 2 0 -150 110 U 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+# Device_Crystal
+#
+DEF Device_Crystal Y 0 40 N N 1 F N
+F0 "Y" 0 150 50 H V C CNN
+F1 "Device_Crystal" 0 -150 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ Crystal*
+$ENDFPLIST
+DRAW
+S -45 100 45 -100 0 1 12 N
+P 2 0 1 0 -100 0 -75 0 N
+P 2 0 1 20 -75 -50 -75 50 N
+P 2 0 1 20 75 -50 75 50 N
+P 2 0 1 0 100 0 75 0 N
+X 1 1 -150 0 50 R 50 50 1 1 P
+X 2 2 150 0 50 L 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+# Device_R_US
+#
+DEF Device_R_US R 0 0 N Y 1 F N
+F0 "R" 100 0 50 V V C CNN
+F1 "Device_R_US" -100 0 50 V V C CNN
+F2 "" 40 -10 50 V I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ R_*
+$ENDFPLIST
+DRAW
+P 2 0 1 0 0 -90 0 -100 N
+P 2 0 1 0 0 90 0 100 N
+P 5 0 1 0 0 -30 40 -45 0 -60 -40 -75 0 -90 N
+P 5 0 1 0 0 30 40 15 0 0 -40 -15 0 -30 N
+P 5 0 1 0 0 90 40 75 0 60 -40 45 0 30 N
+X ~ 1 0 150 50 D 50 50 1 1 P
+X ~ 2 0 -150 50 U 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+# library_DP8340
+#
+DEF library_DP8340 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "library_DP8340" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+S -450 -750 450 750 1 0 0 N
+X DI11 1 -750 550 300 R 50 50 1 1 U
+X DI2 10 -750 -350 300 R 50 50 1 1 U
+X CLK_OUT 11 -750 -450 300 R 50 50 1 1 U
+X GND 12 -750 -550 300 R 50 50 1 1 U
+X X1 13 750 -550 300 L 50 50 1 1 U
+X X2 14 750 -450 300 L 50 50 1 1 U
+X DATA_DLY 15 750 -350 300 L 50 50 1 1 U
+X DATA_OUT1 16 750 -250 300 L 50 50 1 1 U
+X DATA_OUT2 17 750 -150 300 L 50 50 1 1 U
+X EVEN_ODD 18 750 -50 300 L 50 50 1 1 U
+X PARITY_CTL 19 750 50 300 L 50 50 1 1 U
+X DI10 2 -750 450 300 R 50 50 1 1 U
+X TX_ACTIVE 20 750 150 300 L 50 50 1 1 U
+X AUTO_RESP 21 750 250 300 L 50 50 1 1 U
+X REG_FULL 22 750 350 300 L 50 50 1 1 U
+X REG_LOAD 23 750 450 300 L 50 50 1 1 U
+X VCC 24 750 550 300 L 50 50 1 1 U
+X DI9 3 -750 350 300 R 50 50 1 1 U
+X DI8 4 -750 250 300 R 50 50 1 1 U
+X DI7 5 -750 150 300 R 50 50 1 1 U
+X DI6 6 -750 50 300 R 50 50 1 1 U
+X DI5 7 -750 -50 300 R 50 50 1 1 U
+X DI4 8 -750 -150 300 R 50 50 1 1 U
+X DI3 9 -750 -250 300 R 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# library_DP8341
+#
+DEF library_DP8341 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "library_DP8341" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+S -450 -750 450 750 1 0 0 N
+X RX_DISABLE 1 -750 550 300 R 50 50 1 1 U
+X DATA_AVAIL 10 -750 -350 300 R 50 50 1 1 U
+X OUTPUT_CTL 11 -750 -450 300 R 50 50 1 1 U
+X GND 12 -750 -550 300 R 50 50 1 1 U
+X OUTPUT_EN 13 750 -550 300 L 50 50 1 1 U
+X DO2 14 750 -450 300 L 50 50 1 1 U
+X DO3 15 750 -350 300 L 50 50 1 1 U
+X DO4 16 750 -250 300 L 50 50 1 1 U
+X DO5 17 750 -150 300 L 50 50 1 1 U
+X DO6 18 750 -50 300 L 50 50 1 1 U
+X DO7 19 750 50 300 L 50 50 1 1 U
+X +AMP_IN 2 -750 450 300 R 50 50 1 1 U
+X DO8 20 750 150 300 L 50 50 1 1 U
+X DO9 21 750 250 300 L 50 50 1 1 U
+X DO10 22 750 350 300 L 50 50 1 1 U
+X DO11 23 750 450 300 L 50 50 1 1 U
+X VCC 24 750 550 300 L 50 50 1 1 U
+X -AMP_IN 3 -750 350 300 R 50 50 1 1 U
+X DATA 4 -750 250 300 R 50 50 1 1 U
+X DATA_CTL 5 -750 150 300 R 50 50 1 1 U
+X CLOCK 6 -750 50 300 R 50 50 1 1 U
+X RX_ACTIVE 7 -750 -50 300 R 50 50 1 1 U
+X ERROR 8 -750 -150 300 R 50 50 1 1 U
+X REG_READ 9 -750 -250 300 R 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# library_DS3487
+#
+DEF library_DS3487 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "library_DS3487" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "DOCUMENTATION" 0 0 50 H I C CNN
+DRAW
+S -450 -550 450 550 1 0 0 N
+X PIN1 1 -750 350 300 R 50 50 1 1 U
+X PIN10 10 750 -250 300 L 50 50 1 1 U
+X PIN11 11 750 -150 300 L 50 50 1 1 U
+X PIN12 12 750 -50 300 L 50 50 1 1 U
+X PIN13 13 750 50 300 L 50 50 1 1 U
+X PIN14 14 750 150 300 L 50 50 1 1 U
+X PIN15 15 750 250 300 L 50 50 1 1 U
+X PIN16 16 750 350 300 L 50 50 1 1 U
+X PIN2 2 -750 250 300 R 50 50 1 1 U
+X PIN3 3 -750 150 300 R 50 50 1 1 U
+X PIN4 4 -750 50 300 R 50 50 1 1 U
+X PIN5 5 -750 -50 300 R 50 50 1 1 U
+X PIN6 6 -750 -150 300 R 50 50 1 1 U
+X PIN7 7 -750 -250 300 R 50 50 1 1 U
+X PIN8 8 -750 -350 300 R 50 50 1 1 U
+X PIN9 9 750 -350 300 L 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# library_xxxx
+#
+DEF library_xxxx T 0 20 Y N 1 F N
+F0 "T" 0 550 50 H V C CNN
+F1 "library_xxxx" 0 -550 50 H V C CNN
+F2 "Transformer_SMD:Pulse_PA2002NL-PA2008NL-PA2009NL" 0 0 50 H I C CNN
+F3 "" -300 0 50 H I C CNN
+DRAW
+A -100 -90 30 900 -900 0 1 8 N -100 -60 -100 -120
+A -100 -30 30 900 -900 0 1 8 N -100 0 -100 -60
+A -100 30 30 900 -900 0 1 8 N -100 60 -100 0
+A 100 -390 30 -900 900 0 1 8 N 100 -420 100 -360
+A 100 -330 30 -900 900 0 1 8 N 100 -360 100 -300
+A 100 -270 30 -900 900 0 1 8 N 100 -300 100 -240
+A 100 -210 30 -900 900 0 1 8 N 100 -240 100 -180
+A 100 210 30 -900 900 0 1 8 N 100 180 100 240
+A 100 270 30 -900 900 0 1 8 N 100 240 100 300
+A 100 330 30 -900 900 0 1 8 N 100 300 100 360
+A 100 390 30 -900 900 0 1 8 N 100 360 100 420
+A -100 90 30 900 -900 1 1 8 N -100 120 -100 60
+C -100 90 10 0 1 0 F
+C 100 -210 10 0 1 0 F
+C 100 390 10 0 1 0 F
+P 2 0 1 0 -100 -120 -100 -200 N
+P 2 0 1 0 -100 200 -100 120 N
+P 2 0 1 0 -25 425 -25 -425 N
+P 2 0 1 0 25 425 25 -425 N
+P 2 0 1 0 100 -420 100 -500 N
+P 2 0 1 0 100 -100 100 -180 N
+P 2 0 1 0 100 180 100 100 N
+P 2 0 1 0 100 500 100 420 N
+X ~ 1 200 500 100 L 50 50 1 1 P
+X ~ 2 200 100 100 L 50 50 1 1 P
+X ~ 3 -200 200 100 R 50 50 1 1 P
+X ~ 4 -200 -200 100 R 50 50 1 1 P
+X ~ 5 200 -100 100 L 50 50 1 1 P
+X ~ 6 200 -500 100 L 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+# power_GND
+#
+DEF power_GND #PWR 0 0 Y Y 1 F P
+F0 "#PWR" 0 -250 50 H I C CNN
+F1 "power_GND" 0 -150 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+P 6 0 1 0 0 0 0 -50 50 -50 0 -100 -50 -50 0 -50 N
+X GND 1 0 0 0 D 50 50 1 1 W N
+ENDDRAW
+ENDDEF
+#
+# power_VCC
+#
+DEF power_VCC #PWR 0 0 Y Y 1 F P
+F0 "#PWR" 0 -150 50 H I C CNN
+F1 "power_VCC" 0 150 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+C 0 75 25 0 1 0 N
+P 2 0 1 0 0 0 0 50 N
+X VCC 1 0 0 0 U 50 50 1 1 W N
+ENDDRAW
+ENDDEF
+#
+#End Library
--- a/interface1/hardware/hardware-rescue.dcm
+++ b/interface1/hardware/hardware-rescue.dcm
@@ -0,0 +1,3 @@
+EESchema-DOCLIB  Version 2.0
+#
+#End Doc Library
--- a/interface1/hardware/hardware.bak
+++ b/interface1/hardware/hardware.bak
@@ -0,0 +1,557 @@
+EESchema Schematic File Version 4
+EELAYER 29 0
+EELAYER END
+$Descr USLetter 11000 8500
+encoding utf-8
+Sheet 1 1
+Title ""
+Date ""
+Rev ""
+Comp ""
+Comment1 ""
+Comment2 ""
+Comment3 ""
+Comment4 "Based on the typical application from the DP8340 and DP8341 data sheets"
+$EndDescr
+$Comp
+L library:DP8340 U1
+U 1 1 5CFF4259
+P 4200 2500
+F 0 "U1" H 4200 3415 50  0000 C CNN
+F 1 "DP8340" H 4200 3324 50  0000 C CNN
+F 2 "MODULE" H 4200 2500 50  0001 C CNN
+F 3 "" H 4200 2500 50  0001 C CNN
+	1    4200 2500
+	1    0    0    -1  
+$EndComp
+$Comp
+L Device:R_US R7
+U 1 1 5D005C33
+P 5450 3200
+F 0 "R7" H 5518 3246 50  0000 L CNN
+F 1 "500" H 5518 3155 50  0000 L CNN
+F 2 "" V 5490 3190 50  0001 C CNN
+F 3 "~" H 5450 3200 50  0001 C CNN
+	1    5450 3200
+	1    0    0    -1  
+$EndComp
+$Comp
+L Device:Crystal Y1
+U 1 1 5D0074D0
+P 4950 3200
+F 0 "Y1" V 4996 3069 50  0000 R CNN
+F 1 "Crystal" V 4905 3069 50  0000 R CNN
+F 2 "" H 4950 3200 50  0001 C CNN
+F 3 "~" H 4950 3200 50  0001 C CNN
+	1    4950 3200
+	0    -1   -1   0   
+$EndComp
+$Comp
+L power:VCC #PWR?
+U 1 1 5D0081F3
+P 5200 3750
+F 0 "#PWR?" H 5200 3600 50  0001 C CNN
+F 1 "VCC" H 5218 3923 50  0000 C CNN
+F 2 "" H 5200 3750 50  0001 C CNN
+F 3 "" H 5200 3750 50  0001 C CNN
+	1    5200 3750
+	-1   0    0    1   
+$EndComp
+$Comp
+L Device:R_US R1
+U 1 1 5D01411B
+P 8300 1800
+F 0 "R1" V 8505 1800 50  0000 C CNN
+F 1 "150" V 8414 1800 50  0000 C CNN
+F 2 "" V 8340 1790 50  0001 C CNN
+F 3 "~" H 8300 1800 50  0001 C CNN
+	1    8300 1800
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R2
+U 1 1 5D014636
+P 8300 2200
+F 0 "R2" V 8505 2200 50  0000 C CNN
+F 1 "33" V 8414 2200 50  0000 C CNN
+F 2 "" V 8340 2190 50  0001 C CNN
+F 3 "~" H 8300 2200 50  0001 C CNN
+	1    8300 2200
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R4
+U 1 1 5D01DB0F
+P 8300 2600
+F 0 "R4" V 8505 2600 50  0000 C CNN
+F 1 "33" V 8414 2600 50  0000 C CNN
+F 2 "" V 8340 2590 50  0001 C CNN
+F 3 "~" H 8300 2600 50  0001 C CNN
+	1    8300 2600
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R5
+U 1 1 5D01DE87
+P 8300 3000
+F 0 "R5" V 8505 3000 50  0000 C CNN
+F 1 "150" V 8414 3000 50  0000 C CNN
+F 2 "" V 8340 2990 50  0001 C CNN
+F 3 "~" H 8300 3000 50  0001 C CNN
+	1    8300 3000
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R3
+U 1 1 5D026837
+P 8550 2400
+F 0 "R3" H 8618 2446 50  0000 L CNN
+F 1 "510" H 8618 2355 50  0000 L CNN
+F 2 "" V 8590 2390 50  0001 C CNN
+F 3 "~" H 8550 2400 50  0001 C CNN
+	1    8550 2400
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
+	7850 1500 7850 2200
+Wire Wire Line
+	7850 2200 8150 2200
+Wire Wire Line
+	6250 2250 6050 2250
+Wire Wire Line
+	6050 2250 6050 1400
+Wire Wire Line
+	6050 1400 7950 1400
+Wire Wire Line
+	7950 1400 7950 1800
+Wire Wire Line
+	7950 1800 8150 1800
+Wire Wire Line
+	7850 2600 8150 2600
+Wire Wire Line
+	8450 1800 8550 1800
+Wire Wire Line
+	8550 1800 8550 2200
+Wire Wire Line
+	8450 3000 8550 3000
+Wire Wire Line
+	8550 3000 8550 2600
+Wire Wire Line
+	8450 2200 8550 2200
+Connection ~ 8550 2200
+Wire Wire Line
+	8550 2200 8550 2250
+Wire Wire Line
+	8450 2600 8550 2600
+Connection ~ 8550 2600
+Wire Wire Line
+	8550 2600 8550 2550
+Wire Wire Line
+	4950 2850 5600 2850
+Wire Wire Line
+	5600 2850 5600 2050
+Wire Wire Line
+	5600 2050 6250 2050
+$Comp
+L library:DS3487 U?
+U 1 1 5D035700
+P 7000 2400
+F 0 "U?" H 7000 3115 50  0000 C CNN
+F 1 "DS3487" H 7000 3024 50  0000 C CNN
+F 2 "MODULE" H 7000 2400 50  0001 C CNN
+F 3 "" H 7000 2400 50  0001 C CNN
+	1    7000 2400
+	1    0    0    -1  
+$EndComp
+$Comp
+L library:xxxx T1
+U 1 1 5D03C013
+P 9100 2700
+F 0 "T1" H 9100 3381 50  0000 C CNN
+F 1 "xxxx" H 9100 3290 50  0000 C CNN
+F 2 "Transformer_SMD:Pulse_PA2002NL-PA2008NL-PA2009NL" H 9100 2700 50  0001 C CNN
+F 3 "https://productfinder.pulseeng.com/products/datasheets/P663.pdf" H 8800 2700 50  0001 C CNN
+	1    9100 2700
+	-1   0    0    -1  
+$EndComp
+Wire Wire Line
+	8550 2200 8900 2200
+Wire Wire Line
+	8550 2600 8900 2600
+$Comp
+L Connector:Conn_Coaxial J1
+U 1 1 5D047BD2
+P 9700 2500
+F 0 "J1" H 9800 2475 50  0000 L CNN
+F 1 "RG62" H 9800 2384 50  0000 L CNN
+F 2 "" H 9700 2500 50  0001 C CNN
+F 3 " ~" H 9700 2500 50  0001 C CNN
+	1    9700 2500
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
+	9700 2700 9700 2900
+Wire Wire Line
+	9700 2900 9450 2900
+Wire Wire Line
+	9300 2500 9450 2500
+$Comp
+L Device:R_US R6
+U 1 1 5D04B24C
+P 9450 2700
+F 0 "R6" H 9518 2746 50  0000 L CNN
+F 1 "120" H 9518 2655 50  0000 L CNN
+F 2 "" V 9490 2690 50  0001 C CNN
+F 3 "~" H 9450 2700 50  0001 C CNN
+	1    9450 2700
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
+	9450 2550 9450 2500
+Connection ~ 9450 2500
+Wire Wire Line
+	9450 2500 9500 2500
+Wire Wire Line
+	9450 2850 9450 2900
+Connection ~ 9450 2900
+Wire Wire Line
+	9450 2900 9300 2900
+$Comp
+L power:GND #PWR?
+U 1 1 5D04EB7E
+P 6250 3000
+F 0 "#PWR?" H 6250 2750 50  0001 C CNN
+F 1 "GND" H 6255 2827 50  0000 C CNN
+F 2 "" H 6250 3000 50  0001 C CNN
+F 3 "" H 6250 3000 50  0001 C CNN
+	1    6250 3000
+	1    0    0    -1  
+$EndComp
+$Comp
+L power:GND #PWR?
+U 1 1 5D051C9E
+P 3450 3350
+F 0 "#PWR?" H 3450 3100 50  0001 C CNN
+F 1 "GND" H 3455 3177 50  0000 C CNN
+F 2 "" H 3450 3350 50  0001 C CNN
+F 3 "" H 3450 3350 50  0001 C CNN
+	1    3450 3350
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
+	3450 3350 3450 3050
+$Comp
+L Device:C C1
+U 1 1 5D05AC0A
+P 5200 3600
+F 0 "C1" H 5315 3646 50  0000 L CNN
+F 1 "30 pF" H 5315 3555 50  0000 L CNN
+F 2 "" H 5238 3450 50  0001 C CNN
+F 3 "~" H 5200 3600 50  0001 C CNN
+	1    5200 3600
+	1    0    0    -1  
+$EndComp
+$Comp
+L library:DP8341 U2
+U 1 1 5D0650F6
+P 4200 5100
+F 0 "U2" H 4200 4185 50  0000 C CNN
+F 1 "DP8341" H 4200 4276 50  0000 C CNN
+F 2 "MODULE" H 4200 5100 50  0001 C CNN
+F 3 "" H 4200 5100 50  0001 C CNN
+	1    4200 5100
+	-1   0    0    1   
+$EndComp
+Wire Wire Line
+	4950 5550 8700 5550
+Wire Wire Line
+	8700 2800 8900 2800
+Wire Wire Line
+	4950 5450 8800 5450
+Wire Wire Line
+	8800 3200 8900 3200
+Wire Wire Line
+	4950 5650 5750 5650
+Wire Wire Line
+	3450 2950 3200 2950
+Wire Wire Line
+	3200 4050 5250 4050
+Wire Wire Line
+	5250 4050 5250 5150
+Wire Wire Line
+	5250 5150 4950 5150
+Wire Wire Line
+	3450 4650 3100 4650
+Wire Wire Line
+	3100 2850 3450 2850
+Wire Wire Line
+	3450 4750 3000 4750
+Wire Wire Line
+	3000 2750 3450 2750
+Wire Wire Line
+	3450 4850 2900 4850
+Wire Wire Line
+	2900 2650 3450 2650
+Wire Wire Line
+	3450 4950 2800 4950
+Wire Wire Line
+	2800 2550 3450 2550
+Wire Wire Line
+	3450 2450 2700 2450
+Wire Wire Line
+	2700 5050 3450 5050
+Wire Wire Line
+	3450 2350 2600 2350
+Wire Wire Line
+	2600 5150 3450 5150
+Wire Wire Line
+	3450 2250 2500 2250
+Wire Wire Line
+	2500 5250 3450 5250
+Wire Wire Line
+	3450 2150 2400 2150
+Wire Wire Line
+	2400 5350 3450 5350
+Wire Wire Line
+	3450 2050 2300 2050
+Wire Wire Line
+	2300 5450 3450 5450
+Wire Wire Line
+	3450 1950 2200 1950
+Wire Wire Line
+	2200 5550 3450 5550
+Text GLabel 1100 5550 0    50   Input ~ 0
+MEGA22
+Wire Wire Line
+	1100 5550 2200 5550
+Connection ~ 2200 5550
+Text GLabel 1100 5450 0    50   Input ~ 0
+MEGA23
+Wire Wire Line
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+	1    4950 4350
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+L power:VCC #PWR?
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+	1    7750 1750
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+$EndSCHEMATC
--- a/interface1/hardware/hardware.kicad_pcb
+++ b/interface1/hardware/hardware.kicad_pcb
@@ -0,0 +1 @@
+(kicad_pcb (version 4) (host kicad "dummy file") )
--- a/interface1/hardware/hardware.pro
+++ b/interface1/hardware/hardware.pro
@@ -0,0 +1,33 @@
+update=22/05/2015 07:44:53
+version=1
+last_client=kicad
+[general]
+version=1
+RootSch=
+BoardNm=
+[pcbnew]
+version=1
+LastNetListRead=
+UseCmpFile=1
+PadDrill=0.600000000000
+PadDrillOvalY=0.600000000000
+PadSizeH=1.500000000000
+PadSizeV=1.500000000000
+PcbTextSizeV=1.500000000000
+PcbTextSizeH=1.500000000000
+PcbTextThickness=0.300000000000
+ModuleTextSizeV=1.000000000000
+ModuleTextSizeH=1.000000000000
+ModuleTextSizeThickness=0.150000000000
+SolderMaskClearance=0.000000000000
+SolderMaskMinWidth=0.000000000000
+DrawSegmentWidth=0.200000000000
+BoardOutlineThickness=0.100000000000
+ModuleOutlineThickness=0.150000000000
+[cvpcb]
+version=1
+NetIExt=net
+[eeschema]
+version=1
+LibDir=
+[eeschema/libraries]
--- a/interface1/hardware/hardware.sch
+++ b/interface1/hardware/hardware.sch
@@ -0,0 +1,557 @@
+EESchema Schematic File Version 4
+EELAYER 29 0
+EELAYER END
+$Descr USLetter 11000 8500
+encoding utf-8
+Sheet 1 1
+Title ""
+Date ""
+Rev ""
+Comp ""
+Comment1 ""
+Comment2 ""
+Comment3 ""
+Comment4 "Based on the typical application from the DP8340 and DP8341 data sheets"
+$EndDescr
+$Comp
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+F 0 "U1" H 4200 3415 50  0000 C CNN
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+F 2 "MODULE" H 4200 2500 50  0001 C CNN
+F 3 "" H 4200 2500 50  0001 C CNN
+	1    4200 2500
+	1    0    0    -1  
+$EndComp
+$Comp
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+F 2 "" V 5490 3190 50  0001 C CNN
+F 3 "~" H 5450 3200 50  0001 C CNN
+	1    5450 3200
+	1    0    0    -1  
+$EndComp
+$Comp
+L Device:Crystal Y1
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+F 1 "Crystal" V 4905 3069 50  0000 R CNN
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+F 3 "~" H 4950 3200 50  0001 C CNN
+	1    4950 3200
+	0    -1   -1   0   
+$EndComp
+$Comp
+L power:VCC #PWR?
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+F 0 "#PWR?" H 5200 3600 50  0001 C CNN
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+F 2 "" H 5200 3750 50  0001 C CNN
+F 3 "" H 5200 3750 50  0001 C CNN
+	1    5200 3750
+	-1   0    0    1   
+$EndComp
+$Comp
+L Device:R_US R1
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+F 2 "" V 8340 1790 50  0001 C CNN
+F 3 "~" H 8300 1800 50  0001 C CNN
+	1    8300 1800
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R2
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+F 2 "" V 8340 2190 50  0001 C CNN
+F 3 "~" H 8300 2200 50  0001 C CNN
+	1    8300 2200
+	0    -1   -1   0   
+$EndComp
+$Comp
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+F 2 "" V 8340 2590 50  0001 C CNN
+F 3 "~" H 8300 2600 50  0001 C CNN
+	1    8300 2600
+	0    -1   -1   0   
+$EndComp
+$Comp
+L Device:R_US R5
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+F 2 "" V 8340 2990 50  0001 C CNN
+F 3 "~" H 8300 3000 50  0001 C CNN
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+	0    -1   -1   0   
+$EndComp
+$Comp
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+F 2 "" V 8590 2390 50  0001 C CNN
+F 3 "~" H 8550 2400 50  0001 C CNN
+	1    8550 2400
+	1    0    0    -1  
+$EndComp
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+Wire Wire Line
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+F 2 "MODULE" H 7000 2400 50  0001 C CNN
+F 3 "" H 7000 2400 50  0001 C CNN
+	1    7000 2400
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+$Comp
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+F 2 "Transformer_SMD:Pulse_PA2002NL-PA2008NL-PA2009NL" H 9100 2700 50  0001 C CNN
+F 3 "https://productfinder.pulseeng.com/products/datasheets/P663.pdf" H 8800 2700 50  0001 C CNN
+	1    9100 2700
+	-1   0    0    -1  
+$EndComp
+Wire Wire Line
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+Wire Wire Line
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+$Comp
+L Connector:Conn_Coaxial J1
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+F 2 "" H 9700 2500 50  0001 C CNN
+F 3 " ~" H 9700 2500 50  0001 C CNN
+	1    9700 2500
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
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+Wire Wire Line
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+F 2 "" V 9490 2690 50  0001 C CNN
+F 3 "~" H 9450 2700 50  0001 C CNN
+	1    9450 2700
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
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+Wire Wire Line
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+$Comp
+L power:GND #PWR?
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+F 2 "" H 6250 3000 50  0001 C CNN
+F 3 "" H 6250 3000 50  0001 C CNN
+	1    6250 3000
+	1    0    0    -1  
+$EndComp
+$Comp
+L power:GND #PWR?
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+F 2 "" H 3450 3350 50  0001 C CNN
+F 3 "" H 3450 3350 50  0001 C CNN
+	1    3450 3350
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
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+$Comp
+L Device:C C1
+U 1 1 5D05AC0A
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+F 0 "C1" H 5315 3646 50  0000 L CNN
+F 1 "30 pF" H 5315 3555 50  0000 L CNN
+F 2 "" H 5238 3450 50  0001 C CNN
+F 3 "~" H 5200 3600 50  0001 C CNN
+	1    5200 3600
+	1    0    0    -1  
+$EndComp
+$Comp
+L library:DP8341 U2
+U 1 1 5D0650F6
+P 4200 5100
+F 0 "U2" H 4200 4185 50  0000 C CNN
+F 1 "DP8341" H 4200 4276 50  0000 C CNN
+F 2 "MODULE" H 4200 5100 50  0001 C CNN
+F 3 "" H 4200 5100 50  0001 C CNN
+	1    4200 5100
+	-1   0    0    1   
+$EndComp
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+MEGA37
+Text GLabel 1100 4650 0    50   Input ~ 0
+MEGA36
+Wire Wire Line
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+Wire Wire Line
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+Connection ~ 2900 4850
+Wire Wire Line
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+Connection ~ 2800 4950
+Wire Wire Line
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+Connection ~ 2700 5050
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+Connection ~ 2600 5150
+Wire Wire Line
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+Connection ~ 2400 5350
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+MEGA7
+Wire Wire Line
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+MEGA2
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+MEGA4
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+MEGA6
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+$Comp
+L power:GND #PWR?
+U 1 1 5D0CF15F
+P 4950 4350
+F 0 "#PWR?" H 4950 4100 50  0001 C CNN
+F 1 "GND" H 4955 4177 50  0000 C CNN
+F 2 "" H 4950 4350 50  0001 C CNN
+F 3 "" H 4950 4350 50  0001 C CNN
+	1    4950 4350
+	-1   0    0    1   
+$EndComp
+Wire Wire Line
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+MEGA18
+Wire Wire Line
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+MEGA8
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+META9
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+MEGA11
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+MEGA12
+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+Wire Wire Line
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+$Comp
+L power:VCC #PWR?
+U 1 1 5D110504
+P 3450 5900
+F 0 "#PWR?" H 3450 5750 50  0001 C CNN
+F 1 "VCC" H 3468 6073 50  0000 C CNN
+F 2 "" H 3450 5900 50  0001 C CNN
+F 3 "" H 3450 5900 50  0001 C CNN
+	1    3450 5900
+	-1   0    0    1   
+$EndComp
+Wire Wire Line
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+$Comp
+L power:VCC #PWR?
+U 1 1 5D118163
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+F 0 "#PWR?" H 4950 1450 50  0001 C CNN
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+F 2 "" H 4950 1600 50  0001 C CNN
+F 3 "" H 4950 1600 50  0001 C CNN
+	1    4950 1600
+	1    0    0    -1  
+$EndComp
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+Wire Wire Line
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+Wire Wire Line
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+$Comp
+L power:VCC #PWR?
+U 1 1 5D1B82CE
+P 7750 1750
+F 0 "#PWR?" H 7750 1600 50  0001 C CNN
+F 1 "VCC" H 7767 1923 50  0000 C CNN
+F 2 "" H 7750 1750 50  0001 C CNN
+F 3 "" H 7750 1750 50  0001 C CNN
+	1    7750 1750
+	1    0    0    -1  
+$EndComp
+Wire Wire Line
+	6250 2750 6250 3000
+Wire Wire Line
+	7850 3300 6050 3300
+Wire Wire Line
+	6050 3300 6050 2550
+Wire Wire Line
+	6050 2550 6250 2550
+Wire Wire Line
+	7850 2600 7850 3300
+Wire Wire Line
+	6250 2450 6150 2450
+Wire Wire Line
+	6150 2450 6150 1500
+Wire Wire Line
+	6150 1500 7850 1500
+Wire Wire Line
+	6250 2150 5950 2150
+Wire Wire Line
+	5950 2150 5950 3400
+Wire Wire Line
+	5950 3400 7950 3400
+Wire Wire Line
+	7950 3400 7950 3000
+Wire Wire Line
+	7950 3000 8150 3000
+Wire Wire Line
+	7750 1750 7750 2050
+$EndSCHEMATC
--- a/interface1/hardware/library.bck
+++ b/interface1/hardware/library.bck
@@ -0,0 +1,9 @@
+EESchema-DOCLIB  Version 2.0
+#
+$CMP xxxx
+D xxxx
+K pulse
+F https://productfinder.pulseeng.com/products/datasheets/P663.pdf
+$ENDCMP
+#
+#End Doc Library
--- a/interface1/hardware/library.dcm
+++ b/interface1/hardware/library.dcm
@@ -0,0 +1,9 @@
+EESchema-DOCLIB  Version 2.0
+#
+$CMP xxxx
+D xxxx
+K pulse
+F https://productfinder.pulseeng.com/products/datasheets/P663.pdf
+$ENDCMP
+#
+#End Doc Library
--- a/interface1/hardware/library.lib
+++ b/interface1/hardware/library.lib
@@ -0,0 +1,144 @@
+EESchema-LIBRARY Version 2.4
+#encoding utf-8
+#
+# DP8340
+#
+DEF DP8340 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "DP8340" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+S -450 -750 450 750 1 0 0 N
+X DI11 1 -750 550 300 R 50 50 1 1 U
+X DI2 10 -750 -350 300 R 50 50 1 1 U
+X CLK_OUT 11 -750 -450 300 R 50 50 1 1 U
+X GND 12 -750 -550 300 R 50 50 1 1 U
+X X1 13 750 -550 300 L 50 50 1 1 U
+X X2 14 750 -450 300 L 50 50 1 1 U
+X DATA_DLY 15 750 -350 300 L 50 50 1 1 U
+X DATA_OUT1 16 750 -250 300 L 50 50 1 1 U
+X DATA_OUT2 17 750 -150 300 L 50 50 1 1 U
+X EVEN_ODD 18 750 -50 300 L 50 50 1 1 U
+X PARITY_CTL 19 750 50 300 L 50 50 1 1 U
+X DI10 2 -750 450 300 R 50 50 1 1 U
+X TX_ACTIVE 20 750 150 300 L 50 50 1 1 U
+X AUTO_RESP 21 750 250 300 L 50 50 1 1 U
+X REG_FULL 22 750 350 300 L 50 50 1 1 U
+X REG_LOAD 23 750 450 300 L 50 50 1 1 U
+X VCC 24 750 550 300 L 50 50 1 1 U
+X DI9 3 -750 350 300 R 50 50 1 1 U
+X DI8 4 -750 250 300 R 50 50 1 1 U
+X DI7 5 -750 150 300 R 50 50 1 1 U
+X DI6 6 -750 50 300 R 50 50 1 1 U
+X DI5 7 -750 -50 300 R 50 50 1 1 U
+X DI4 8 -750 -150 300 R 50 50 1 1 U
+X DI3 9 -750 -250 300 R 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# DP8341
+#
+DEF DP8341 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "DP8341" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+S -450 -750 450 750 1 0 0 N
+X RX_DISABLE 1 -750 550 300 R 50 50 1 1 U
+X DATA_AVAIL 10 -750 -350 300 R 50 50 1 1 U
+X OUTPUT_CTL 11 -750 -450 300 R 50 50 1 1 U
+X GND 12 -750 -550 300 R 50 50 1 1 U
+X OUTPUT_EN 13 750 -550 300 L 50 50 1 1 U
+X DO2 14 750 -450 300 L 50 50 1 1 U
+X DO3 15 750 -350 300 L 50 50 1 1 U
+X DO4 16 750 -250 300 L 50 50 1 1 U
+X DO5 17 750 -150 300 L 50 50 1 1 U
+X DO6 18 750 -50 300 L 50 50 1 1 U
+X DO7 19 750 50 300 L 50 50 1 1 U
+X +AMP_IN 2 -750 450 300 R 50 50 1 1 U
+X DO8 20 750 150 300 L 50 50 1 1 U
+X DO9 21 750 250 300 L 50 50 1 1 U
+X DO10 22 750 350 300 L 50 50 1 1 U
+X DO11 23 750 450 300 L 50 50 1 1 U
+X VCC 24 750 550 300 L 50 50 1 1 U
+X -AMP_IN 3 -750 350 300 R 50 50 1 1 U
+X DATA 4 -750 250 300 R 50 50 1 1 U
+X DATA_CTL 5 -750 150 300 R 50 50 1 1 U
+X CLOCK 6 -750 50 300 R 50 50 1 1 U
+X RX_ACTIVE 7 -750 -50 300 R 50 50 1 1 U
+X ERROR 8 -750 -150 300 R 50 50 1 1 U
+X REG_READ 9 -750 -250 300 R 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# DS3487
+#
+DEF DS3487 U 0 40 Y Y 1 F N
+F0 "U" 0 -100 50 H V C CNN
+F1 "DS3487" 0 100 50 H V C CNN
+F2 "MODULE" 0 0 50 H I C CNN
+F3 "DOCUMENTATION" 0 0 50 H I C CNN
+DRAW
+S -450 -550 450 550 1 0 0 N
+X PIN1 1 -750 350 300 R 50 50 1 1 U
+X PIN10 10 750 -250 300 L 50 50 1 1 U
+X PIN11 11 750 -150 300 L 50 50 1 1 U
+X PIN12 12 750 -50 300 L 50 50 1 1 U
+X PIN13 13 750 50 300 L 50 50 1 1 U
+X PIN14 14 750 150 300 L 50 50 1 1 U
+X PIN15 15 750 250 300 L 50 50 1 1 U
+X PIN16 16 750 350 300 L 50 50 1 1 U
+X PIN2 2 -750 250 300 R 50 50 1 1 U
+X PIN3 3 -750 150 300 R 50 50 1 1 U
+X PIN4 4 -750 50 300 R 50 50 1 1 U
+X PIN5 5 -750 -50 300 R 50 50 1 1 U
+X PIN6 6 -750 -150 300 R 50 50 1 1 U
+X PIN7 7 -750 -250 300 R 50 50 1 1 U
+X PIN8 8 -750 -350 300 R 50 50 1 1 U
+X PIN9 9 750 -350 300 L 50 50 1 1 U
+ENDDRAW
+ENDDEF
+#
+# xxxx
+#
+DEF xxxx T 0 20 Y N 1 F N
+F0 "T" 0 550 50 H V C CNN
+F1 "xxxx" 0 -550 50 H V C CNN
+F2 "Transformer_SMD:Pulse_PA2002NL-PA2008NL-PA2009NL" 0 0 50 H I C CNN
+F3 "" -300 0 50 H I C CNN
+DRAW
+A -100 -90 30 900 -900 0 1 8 N -100 -60 -100 -120
+A -100 -30 30 900 -900 0 1 8 N -100 0 -100 -60
+A -100 30 30 900 -900 0 1 8 N -100 60 -100 0
+A 100 -390 30 -900 900 0 1 8 N 100 -420 100 -360
+A 100 -330 30 -900 900 0 1 8 N 100 -360 100 -300
+A 100 -270 30 -900 900 0 1 8 N 100 -300 100 -240
+A 100 -210 30 -900 900 0 1 8 N 100 -240 100 -180
+A 100 210 30 -900 900 0 1 8 N 100 180 100 240
+A 100 270 30 -900 900 0 1 8 N 100 240 100 300
+A 100 330 30 -900 900 0 1 8 N 100 300 100 360
+A 100 390 30 -900 900 0 1 8 N 100 360 100 420
+A -100 90 30 900 -900 1 1 8 N -100 120 -100 60
+C -100 90 10 0 1 0 F
+C 100 -210 10 0 1 0 F
+C 100 390 10 0 1 0 F
+P 2 0 1 0 -100 -120 -100 -200 N
+P 2 0 1 0 -100 200 -100 120 N
+P 2 0 1 0 -25 425 -25 -425 N
+P 2 0 1 0 25 425 25 -425 N
+P 2 0 1 0 100 -420 100 -500 N
+P 2 0 1 0 100 -100 100 -180 N
+P 2 0 1 0 100 180 100 100 N
+P 2 0 1 0 100 500 100 420 N
+X ~ 1 200 500 100 L 50 50 1 1 P
+X ~ 2 200 100 100 L 50 50 1 1 P
+X ~ 3 -200 200 100 R 50 50 1 1 P
+X ~ 4 -200 -200 100 R 50 50 1 1 P
+X ~ 5 200 -100 100 L 50 50 1 1 P
+X ~ 6 200 -500 100 L 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+#End Library
--- a/interface1/hardware/schematic.svg
+++ b/interface1/hardware/schematic.svg
--- a/interface1/hardware/sym-lib-table
+++ b/interface1/hardware/sym-lib-table
@@ -0,0 +1,3 @@
+(sym_lib_table
+  (lib (name library)(type Legacy)(uri ${KIPRJMOD}/library.lib)(options "")(descr ""))
+)
--- a/pycoax/.gitignore
+++ b/pycoax/.gitignore
@@ -0,0 +1,112 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# celery beat schedule file
+celerybeat-schedule
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+VIRTUALENV/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
--- a/pycoax/LICENSE
+++ b/pycoax/LICENSE
@@ -0,0 +1,13 @@
+Copyright (c) 2019, Andrew Kay
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
--- a/pycoax/README.md
+++ b/pycoax/README.md
@@ -0,0 +1,9 @@
+# pycoax
+
+Python IBM 3270 coaxial interface library.
+
+## Use
+
+You will need to build a [interface](../interface1) and connect it to your computer.
+
+See [examples](examples) for complete examples.
--- a/pycoax/coax/about.py
+++ b/pycoax/coax/about.py
@@ -0,0 +1 @@
+__version__ = '0.1.0'
--- a/pycoax/coax/init.py
+++ b/pycoax/coax/init.py
@@ -0,0 +1,39 @@
+from .__about__ import __version__
+
+from .interface1 import Interface1
+
+from .protocol import (
+    PollResponse,
+    PowerOnResetCompletePollResponse,
+    KeystrokePollResponse,
+    poll,
+    poll_ack,
+    read_status,
+    read_terminal_id,
+    read_extended_id,
+    read_address_counter_hi,
+    read_address_counter_lo,
+    read_data,
+    read_multiple,
+    reset,
+    load_control_register,
+    load_secondary_control,
+    load_mask,
+    load_address_counter_hi,
+    load_address_counter_lo,
+    write_data,
+    clear,
+    search_forward,
+    search_backward,
+    insert_byte,
+    start_operation,
+    diagnostic_reset
+)
+
+from .exceptions import (
+    InterfaceError,
+    ReceiveError,
+    InterfaceTimeout,
+    ReceiveTimeout,
+    ProtocolError
+)
--- a/pycoax/coax/exceptions.py
+++ b/pycoax/coax/exceptions.py
@@ -0,0 +1,19 @@
+"""
+coax.exceptions
+~~~~~~~~~~~~~~~
+"""
+
+class InterfaceError(Exception):
+    """An interface error occurred."""
+
+class ReceiveError(Exception):
+    """A receive error occurred."""
+
+class InterfaceTimeout(Exception):
+    """The interface timed out."""
+
+class ReceiveTimeout(Exception):
+    """The receive operation timed out."""
+
+class ProtocolError(Exception):
+    """A protocol error occurred."""
--- a/pycoax/coax/interface1.py
+++ b/pycoax/coax/interface1.py
@@ -0,0 +1,218 @@
+"""
+coax.interface1
+~~~~~~~~~~~~~~~
+"""
+
+from enum import Flag
+import itertools
+import struct
+from sliplib import SlipWrapper, ProtocolError
+
+from .exceptions import InterfaceError, InterfaceTimeout, ReceiveError, ReceiveTimeout
+
+class Interface1:
+    """A serial attached Arduino interface using the National Semiconductor
+    DP8340 and DP8341.
+    """
+
+    def __init__(self, serial):
+        if serial is None:
+            raise ValueError('Serial port is required')
+
+        self.serial = serial
+
+        self.slip_serial = SlipSerial(self.serial)
+
+    def reset(self):
+        """Reset the interface."""
+        original_serial_timeout = self.serial.timeout
+
+        self.serial.reset_input_buffer()
+
+        self._write_message(b'\x01')
+
+        self.serial.timeout = 5
+
+        try:
+            message = self._read_message()
+        finally:
+            self.serial.timeout = original_serial_timeout
+
+        if message[0] != 0x01:
+            raise _convert_error(message)
+
+        if len(message) != 4:
+            raise InterfaceError('Invalid reset response')
+
+        (major, minor, patch) = struct.unpack('BBB', message[1:])
+
+        return '{}.{}.{}'.format(major, minor, patch)
+
+    def execute(self, command_word, data=None, response_length=1, timeout=None):
+        """Executes a command.
+
+        :param command_word: the command to execute
+        :param data: optional bytearray containing command data
+        :param response_length: the expected response length
+        :param timeout: optional timeout in seconds
+        """
+        timeout_milliseconds = 0
+
+        if timeout:
+            if self.serial.timeout and timeout > self.serial.timeout:
+                raise ValueError('Timeout cannot be greater than serial timeout')
+
+            timeout_milliseconds = int(timeout * 1000)
+
+        message = struct.pack(">BHHH", 0x02, command_word, response_length,
+                              timeout_milliseconds)
+
+        if data is not None:
+            message += data
+
+        self._write_message(message)
+
+        message = self._read_message()
+
+        if message[0] != 0x01:
+            raise _convert_error(message)
+
+        response_bytes = message[1:]
+
+        response_words = [(hi << 8) | lo for (lo, hi) in zip(response_bytes[::2],
+                                                             response_bytes[1::2])]
+
+        # Handle any receiver (DP8341) errors that are included in the response words.
+        error_words = [word for word in response_words if (word & 0x8000) == 0x8000]
+
+        if error_words:
+            raise _convert_receiver_errors(error_words)
+
+        return response_words
+
+    def offload_load_address_counter(self, address):
+        """Executes a combined LO and HI address counter load.
+
+        :param address: the address
+        """
+        parameters = struct.pack(">H", address)
+
+        self._execute_offload(0x01, parameters)
+
+    def offload_write(self, data, address=None, restore_original_address=False, repeat=0):
+        """Executes a complex write operation.
+
+        :param data: the data
+        :param address: optional address to load before WRITE_DATA command
+        :param restore_original_address: restore the original data after write
+        :param repeat: repeat the data
+        """
+        parameters = struct.pack(">HBH", 0xffff if address is None else address,
+                                 0x01 if restore_original_address else 0x00,
+                                 repeat) + data
+
+        self._execute_offload(0x02, parameters)
+
+    def _execute_offload(self, command, parameters=None):
+        """Executes an offloaded command."""
+        message = struct.pack("BB", 0x03, command)
+
+        if parameters:
+            message += parameters
+
+        self._write_message(message)
+
+        message = self._read_message()
+
+        if message[0] != 0x01:
+            raise _convert_error(message)
+
+    def _read_message(self):
+        try:
+            message = self.slip_serial.recv_msg()
+        except ProtocolError:
+            raise InterfaceError('SLIP protocol error')
+
+        if len(message) < 4:
+            raise InterfaceError('Invalid response message')
+
+        (length,) = struct.unpack(">H", message[:2])
+
+        if length != len(message) - 4:
+            raise InterfaceError('Response message length mismatch')
+
+        if length < 1:
+            raise InterfaceError('Empty response message')
+
+        return message[2:-2]
+
+    def _write_message(self, message):
+        self.slip_serial.send_msg(struct.pack(">H", len(message)) + message + struct.pack(">H", 0))
+
+ERROR_MAP = {
+    1: InterfaceError('Invalid request message'),
+    2: InterfaceError('Unknown command'),
+    3: InterfaceError('Unknown offload command'),
+
+    101: InterfaceError('Receiver active'),
+    102: ReceiveTimeout(),
+    103: ReceiveError('Receiver buffer overflow')
+}
+
+def _convert_error(message):
+    if message[0] != 0x02:
+        return InterfaceError('Invalid response')
+
+    if len(message) < 2:
+        return InterfaceError('Invalid error response')
+
+    if message[1] in ERROR_MAP:
+        return ERROR_MAP[message[1]]
+
+    return InterfaceError('Unknown error')
+
+class ReceiverErrorCode(Flag):
+    """Receiver (DP8341) error code."""
+    DATA_OVERFLOW = 0x01
+    PARITY = 0x02
+    TRANSMIT_CHECK_CONDITIONS = 0x04
+    INVALID_ENDING_SEQUENCE = 0x08
+    MID_BID_TRANSITION = 0x10
+    STARTING_SEQUENCE = 0x20
+    RECEIVER_DISABLED = 0x40
+
+def _parse_receiver_error(word):
+    return [code for code in ReceiverErrorCode if code & ReceiverErrorCode(word & 0x7f)]
+
+def _convert_receiver_errors(words):
+    codes = set(itertools.chain.from_iterable([_parse_receiver_error(word) for word
+                                               in words]))
+
+    message = 'Receiver ' + ', '.join([code.name for code in codes]) + ' error'
+
+    raise ReceiveError(message)
+
+class SlipSerial(SlipWrapper):
+    """sliplib wrapper for pySerial."""
+
+    def send_bytes(self, packet):
+        """Sends a packet over the serial port."""
+        self.stream.write(packet)
+        self.stream.flush()
+
+    def recv_bytes(self):
+        """Receive data from the serial port."""
+        if self.stream.closed:
+            return b''
+
+        count = self.stream.in_waiting
+
+        if count:
+            return self.stream.read(count)
+
+        byte = self.stream.read(1)
+
+        if byte == b'':
+            raise InterfaceTimeout()
+
+        return byte
--- a/pycoax/coax/parity.py
+++ b/pycoax/coax/parity.py
@@ -0,0 +1,26 @@
+"""
+coax.parity
+~~~~~~~~~~~
+
+Single byte parity computation
+"""
+
+# From http://p-nand-q.com/python/algorithms/math/bit-parity.html
+def _parallel_swar(i):
+    i = i - ((i >> 1) & 0x55555555)
+    i = (i & 0x33333333) + ((i >> 2) & 0x33333333)
+    i = (((i + (i >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24
+    return int(i % 2)
+
+_PARITY_LOOKUP = [_parallel_swar(i) for i in range(256)]
+
+def even_parity(byte):
+    """Compute even parity"""
+    if byte < 0 or byte > 255:
+        raise ValueError('Input must be between 0 and 255')
+
+    return _PARITY_LOOKUP[byte]
+
+def odd_parity(byte):
+    """Compute odd parity"""
+    return int(not even_parity(byte))
--- a/pycoax/coax/protocol.py
+++ b/pycoax/coax/protocol.py
@@ -0,0 +1,238 @@
+"""
+coax.protocol
+~~~~~~~~~~~~~
+"""
+
+from enum import Enum
+
+from .exceptions import ProtocolError
+from .parity import odd_parity
+
+class Command(Enum):
+    """Terminal command."""
+
+    # Read Commands
+    POLL = 0x01
+    POLL_ACK = 0x11
+    READ_STATUS = 0x0d
+    READ_TERMINAL_ID = 0x09
+    READ_EXTENDED_ID = 0x07
+    READ_ADDRESS_COUNTER_HI = 0x05
+    READ_ADDRESS_COUNTER_LO = 0x15
+    READ_DATA = 0x03
+    READ_MULTIPLE = 0x0b
+
+    # Write Commands
+    RESET = 0x02
+    LOAD_CONTROL_REGISTER = 0x0a
+    LOAD_SECONDARY_CONTROL = 0x1a
+    LOAD_MASK = 0x16
+    LOAD_ADDRESS_COUNTER_HI = 0x04
+    LOAD_ADDRESS_COUNTER_LO = 0x14
+    WRITE_DATA = 0x0c
+    CLEAR = 0x06
+    SEARCH_FORWARD = 0x10
+    SEARCH_BACKWARD = 0x12
+    INSERT_BYTE = 0x0e
+    START_OPERATION = 0x08
+    DIAGNOSTIC_RESET = 0x1c
+
+class PollResponse:
+    """Terminal POLL response."""
+
+    @staticmethod
+    def is_power_on_reset_complete(value):
+        """Is the response word a power on reset complete response?"""
+        return value == 0xa
+
+    @staticmethod
+    def is_keystroke(value):
+        """Is the response word a keystroke response?"""
+        return ((value & 0x2) == 0x2) and ((value & 0x1) == 0)
+
+    def __init__(self, value):
+        self.value = value
+
+class PowerOnResetCompletePollResponse(PollResponse):
+    """Terminal power-on-reset complete poll response."""
+
+    def __init__(self, value):
+        if not PollResponse.is_power_on_reset_complete(value):
+            raise ValueError('Invalid POR poll response')
+
+        super().__init__(value)
+
+class KeystrokePollResponse(PollResponse):
+    """Terminal keystroke poll response."""
+
+    def __init__(self, value):
+        if not PollResponse.is_keystroke(value):
+            raise ValueError('Invalid keystroke poll response')
+
+        super().__init__(value)
+
+        self.scan_code = (value >> 2) & 0xff
+
+class TerminalId:
+    """Terminal model and keyboard."""
+
+    def __init__(self, value):
+        if (value & 0x1) != 0:
+            raise ValueError('Invalid terminal identifier')
+
+        self.value = value
+
+        self.model = (value & 0x0e) >> 1
+        self.keyboard = (value & 0xf0) >> 4
+
+def poll(interface, **kwargs):
+    """Execute a POLL command."""
+    command_word = _pack_command_word(Command.POLL)
+
+    response = interface.execute(command_word, **kwargs)
+
+    if len(response) != 1:
+        raise ProtocolError('Expected 1 word POLL response')
+
+    word = response[0]
+
+    if word == 0:
+        return None
+
+    if PollResponse.is_power_on_reset_complete(word):
+        return PowerOnResetCompletePollResponse(word)
+
+    if PollResponse.is_keystroke(word):
+        return KeystrokePollResponse(word)
+
+    return PollResponse(word)
+
+def poll_ack(interface, **kwargs):
+    """Execute a POLL_ACK command."""
+    _execute_write_command(interface, Command.POLL_ACK, **kwargs)
+
+def read_status(interface):
+    """Execute a READ_STATUS command."""
+    raise NotImplementedError
+
+def read_terminal_id(interface, **kwargs):
+    """Execute a READ_TERMINAL_ID command."""
+    response = _execute_read_command(interface, Command.READ_TERMINAL_ID, **kwargs)
+
+    return TerminalId(response[0])
+
+def read_extended_id(interface, **kwargs):
+    """Execute a READ_EXTENDED_ID command."""
+    return _execute_read_command(interface, Command.READ_EXTENDED_ID, 4, **kwargs)
+
+def read_address_counter_hi(interface, **kwargs):
+    """Execute a READ_ADDRESS_COUNTER_HI command."""
+    return _execute_read_command(interface, Command.READ_ADDRESS_COUNTER_HI, **kwargs)[0]
+
+def read_address_counter_lo(interface, **kwargs):
+    """Execute a READ_ADDRESS_COUTER_LO command."""
+    return _execute_read_command(interface, Command.READ_ADDRESS_COUNTER_LO, **kwargs)[0]
+
+def read_data(interface):
+    """Execute a READ_DATA command."""
+    raise NotImplementedError
+
+def read_multiple(interface):
+    """Execute a READ_MULTIPLE command."""
+    raise NotImplementedError
+
+def reset(interface):
+    """Execute a RESET command."""
+    raise NotImplementedError
+
+def load_control_register(interface):
+    """Execute a LOAD_CONTROL_REGISTER command."""
+    raise NotImplementedError
+
+def load_secondary_control(interface):
+    """Execute a LOAD_SECONDARY_CONTROL command."""
+    raise NotImplementedError
+
+def load_mask(interface):
+    """Execute a LOAD_MASK command."""
+    raise NotImplementedError
+
+def load_address_counter_hi(interface, address, **kwargs):
+    """Execute a LOAD_ADDRESS_COUNTER_HI command."""
+    _execute_write_command(interface, Command.LOAD_ADDRESS_COUNTER_HI, bytes([address]), **kwargs)
+
+def load_address_counter_lo(interface, address, **kwargs):
+    """Execute a LOAD_ADDRESS_COUNTER_LO command."""
+    _execute_write_command(interface, Command.LOAD_ADDRESS_COUNTER_LO, bytes([address]), **kwargs)
+
+def write_data(interface, data, **kwargs):
+    """Execute a WRITE_DATA command."""
+    _execute_write_command(interface, Command.WRITE_DATA, data, **kwargs)
+
+def clear(interface):
+    """Execute a CLEAR command."""
+    raise NotImplementedError
+
+def search_forward(interface):
+    """Execute a SEARCH_FORWARD command."""
+    raise NotImplementedError
+
+def search_backward(interface):
+    """Execute a SEARCH_BACKWARD command."""
+    raise NotImplementedError
+
+def insert_byte(interface):
+    """Execute a INSERT_BYTE command."""
+    raise NotImplementedError
+
+def start_operation(interface):
+    """Execute a START_OPERATION command."""
+    raise NotImplementedError
+
+def diagnostic_reset(interface):
+    """Execute a DIAGNOSTIC_RESET command."""
+    raise NotImplementedError
+
+def _execute_read_command(interface, command, response_length=1):
+    """Execute a standard read command."""
+    command_word = _pack_command_word(command)
+
+    response_words = interface.execute(command_word, response_length=response_length)
+
+    if len(response_words) != response_length:
+        raise ProtocolError(f'Expected {response_length} word {command.name} response')
+
+    return _unpack_data_words(response_words)
+
+def _execute_write_command(interface, command, data=None):
+    """Execute a standard write command."""
+    command_word = _pack_command_word(command)
+
+    response_words = interface.execute(command_word, data)
+
+    if len(response_words) != 1:
+        raise ProtocolError(f'Expected 1 word {command.name} response')
+
+    if response_words[0] != 0:
+        raise ProtocolError('Expected TR/TA response')
+
+def _pack_command_word(command, address=0):
+    """Pack a command and address into a 10-bit command word for the interface."""
+    return (address << 7) | (command.value << 2) | 0x1
+
+def _unpack_data_words(words):
+    """Unpack the data bytes from 10-bit data words, performs parity checking."""
+    return bytes([_unpack_data_word(word) for word in words])
+
+def _unpack_data_word(word):
+    """Unpack the data byte from a 10-bit data word, performs parity checking."""
+    if not (word & 0x1) == 0x0:
+        raise ProtocolError('Word does not have data bit set')
+
+    byte = (word >> 2) & 0xff
+    parity = (word >> 1) & 0x1
+
+    if not odd_parity(byte) == parity:
+        raise ProtocolError('Parity error')
+
+    return byte
--- a/pycoax/examples/01_reset.py
+++ b/pycoax/examples/01_reset.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from serial import Serial
+
+sys.path.append('..')
+
+from coax import Interface1, poll, poll_ack
+
+print('Opening serial port...')
+
+with Serial('/dev/ttyUSB0', 115200) as serial:
+    print('Sleeping to allow interface time to wake up...')
+
+    time.sleep(3)
+
+    interface = Interface1(serial)
+
+    print('Resetting interface...')
+
+    version = interface.reset()
+
+    print(f'Firmware version is {version}')
--- a/pycoax/examples/02_poll.py
+++ b/pycoax/examples/02_poll.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from serial import Serial
+
+sys.path.append('..')
+
+from coax import Interface1, poll, poll_ack
+
+print('Opening serial port...')
+
+with Serial('/dev/ttyUSB0', 115200) as serial:
+    print('Sleeping to allow interface time to wake up...')
+
+    time.sleep(3)
+
+    interface = Interface1(serial)
+
+    print('Resetting interface...')
+
+    version = interface.reset()
+
+    print(f'Firmware version is {version}')
+
+    print('POLL...')
+
+    poll_response = poll(interface, timeout=5)
+
+    print(poll_response)
+
+    if poll_response:
+        print('POLL_ACK...')
+
+        poll_ack(interface)
--- a/pycoax/examples/03_read_terminal_id.py
+++ b/pycoax/examples/03_read_terminal_id.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from serial import Serial
+
+sys.path.append('..')
+
+from coax import Interface1, read_terminal_id
+
+print('Opening serial port...')
+
+with Serial('/dev/ttyUSB0', 115200) as serial:
+    print('Sleeping to allow interface time to wake up...')
+
+    time.sleep(3)
+
+    interface = Interface1(serial)
+
+    print('Resetting interface...')
+
+    version = interface.reset()
+
+    print(f'Firmware version is {version}')
+
+    print('READ_TERMINAL_ID...')
+
+    terminal_id = read_terminal_id(interface)
+
+    print(terminal_id)
--- a/pycoax/examples/04_hello_world.py
+++ b/pycoax/examples/04_hello_world.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from serial import Serial
+
+sys.path.append('..')
+
+from coax import Interface1, read_address_counter_hi, read_address_counter_lo, load_address_counter_hi, load_address_counter_lo, write_data
+
+print('Opening serial port...')
+
+with Serial('/dev/ttyUSB0', 115200) as serial:
+    print('Sleeping to allow interface time to wake up...')
+
+    time.sleep(3)
+
+    interface = Interface1(serial)
+
+    print('Resetting interface...')
+
+    version = interface.reset()
+
+    print(f'Firmware version is {version}')
+
+    print('LOAD_ADDRESS_COUNTER_HI...')
+
+    load_address_counter_hi(interface, 0)
+
+    print('LOAD_ADDRESS_COUNTER_LO...')
+
+    load_address_counter_lo(interface, 80)
+
+    print('WRITE_DATA...')
+
+    write_data(interface, bytes.fromhex('a7 84 8b 8b 8e 33 00 96 8e 91 8b 83 19'))
+
+    print('READ_ADDRESS_COUNTER_HI...')
+
+    hi = read_address_counter_hi(interface)
+
+    print('READ_ADDRESS_COUNTER_LO...')
+
+    lo = read_address_counter_lo(interface)
+
+    print(f'hi = {hi:02x}, lo = {lo:02x}')
--- a/pycoax/examples/05_offload_write.py
+++ b/pycoax/examples/05_offload_write.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from serial import Serial
+
+sys.path.append('..')
+
+from coax import Interface1
+
+print('Opening serial port...')
+
+with Serial('/dev/ttyUSB0', 115200) as serial:
+    print('Sleeping to allow interface time to wake up...')
+
+    time.sleep(3)
+
+    interface = Interface1(serial)
+
+    print('Resetting interface...')
+
+    version = interface.reset()
+
+    print(f'Firmware version is {version}')
+
+    for n in range(10):
+        print(f'Writing line {n + 1}...')
+
+        address = ((7 + n) * 80) + 80
+
+        interface.offload_write(b'\x80', address=address, repeat=n)
--- a/pycoax/requirements.txt
+++ b/pycoax/requirements.txt
@@ -0,0 +1,2 @@
+pyserial==3.4
+sliplib==0.3.0
--- a/pycoax/run_unit_tests.sh
+++ b/pycoax/run_unit_tests.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+python -m unittest discover tests
--- a/pycoax/setup.py
+++ b/pycoax/setup.py
@@ -0,0 +1,35 @@
+import os
+from setuptools import setup
+
+ABOUT = {}
+
+with open(os.path.join(os.path.dirname(__file__), "coax", "__about__.py")) as file:
+    exec(file.read(), ABOUT)
+
+LONG_DESCRIPTION = """# pycoax
+
+Python IBM 3270 coaxial interface library.
+
+See [GitHub](https://github.com/lowobservable/coax-interface#readme) for more information.
+"""
+
+setup(
+    name='pycoax',
+    version=ABOUT['__version__'],
+    description='IBM 3270 coaxial interface',
+    url='https://github.com/lowobservable/coax-interface',
+    author='Andrew Kay',
+    author_email='projects@ajk.me',
+    packages=['coax'],
+    install_requires=['pyserial==3.4', 'sliplib==0.3.0'],
+    long_description=LONG_DESCRIPTION,
+    long_description_content_type='text/markdown',
+    classifiers=[
+        'Development Status :: 3 - Alpha',
+        'License :: OSI Approved :: ISC License (ISCL)',
+        'Operating System :: OS Independent',
+        'Programming Language :: Python :: 3',
+        'Topic :: Communications',
+        'Topic :: Terminals'
+    ]
+)
--- a/pycoax/tests/init.py
+++ b/pycoax/tests/init.py
--- a/pycoax/tests/context.py
+++ b/pycoax/tests/context.py
@@ -0,0 +1,4 @@
+import sys
+import os
+
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
--- a/pycoax/tests/test_interface1.py
+++ b/pycoax/tests/test_interface1.py
@@ -0,0 +1,264 @@
+import unittest
+from unittest.mock import Mock
+import sliplib
+
+import context
+
+from coax import Interface1, InterfaceError, ReceiveError, ReceiveTimeout
+
+class Interface1ResetTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.serial.timeout = None
+
+        self.interface = Interface1(self.serial)
+
+        self.interface._write_message = Mock()
+        self.interface._read_message = Mock(return_value=bytes.fromhex('01 01 02 03'))
+
+    def test_message_is_sent(self):
+        # Act
+        self.interface.reset()
+
+        # Assert
+        self.interface._write_message.assert_called_with(bytes.fromhex('01'))
+
+    def test_version_is_formatted_correctly(self):
+        self.assertEqual(self.interface.reset(), '1.2.3')
+
+    def test_timeout_is_restored_after_reset(self):
+        # Arrange
+        self.serial.timeout = 123
+
+        # Act
+        self.interface.reset()
+
+        # Assert
+        self.assertEqual(self.serial.timeout, 123)
+
+    def test_invalid_message_length_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('01 01'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Invalid reset response'):
+            self.interface.reset()
+
+    def test_error_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('02 01'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Invalid request message'):
+            self.interface.reset()
+
+class Interface1ExecuteTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.serial.timeout = None
+
+        self.interface = Interface1(self.serial)
+
+        self.interface._write_message = Mock()
+        self.interface._read_message = Mock(return_value=bytes.fromhex('01 00'))
+
+    def test_message_is_sent_without_data(self):
+        # Act
+        self.interface.execute(0b0000001001)
+
+        # Assert
+        self.interface._write_message.assert_called_with(bytes.fromhex('02 00 09 00 01 00 00'))
+
+    def test_message_is_sent_with_data(self):
+        # Act
+        self.interface.execute(0b0000110001, data=bytes.fromhex('de ad be ef'))
+
+        # Assert
+        self.interface._write_message.assert_called_with(bytes.fromhex('02 00 31 00 01 00 00 de ad be ef'))
+
+    def test_message_is_sent_with_response_length(self):
+        # Act
+        self.interface.execute(0b0000011101, response_length=4)
+
+        # Assert
+        self.interface._write_message.assert_called_with(bytes.fromhex('02 00 1d 00 04 00 00'))
+
+    def test_timeout_cannot_exceed_serial_timeout(self):
+        # Arrange
+        self.serial.timeout = 2.0
+
+        # Act and assert
+        with self.assertRaisesRegex(ValueError, 'Timeout cannot be greater than serial timeout'):
+            self.interface.execute(0b0000000101, timeout=3)
+
+    def test_message_is_sent_with_timeout(self):
+        # Act
+        self.interface.execute(0b0000000101, timeout=3)
+
+        # Assert
+        self.interface._write_message.assert_called_with(bytes.fromhex('02 00 05 00 01 0b b8'))
+
+    # TODO... interface timeout...
+
+    def test_receive_timeout_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('02 66'))
+
+        # Act and assert
+        with self.assertRaises(ReceiveTimeout):
+            self.interface.execute(0b0000000101)
+
+    def test_receive_error_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('02 67'))
+
+        # Act and assert
+        with self.assertRaisesRegex(ReceiveError, 'Receiver buffer overflow'):
+            self.interface.execute(0b0000000101)
+
+    def test_interface_error_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('03'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Invalid response'):
+            self.interface.execute(0b0000000101)
+
+    def test_response_words_are_unpacked(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('01 01 02 03 04'))
+
+        # Act
+        response_words = self.interface.execute(0b0000011101, response_length=4)
+
+        # Assert
+        self.assertEqual(response_words, [0x0201, 0x0403])
+
+    def test_receiver_error_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('01 a0 80'))
+
+        # Act and assert
+        with self.assertRaisesRegex(ReceiveError, 'Receiver STARTING_SEQUENCE error'):
+            self.interface.execute(0b0000011101, response_length=4)
+
+class Interface1OffloadLoadAddressCounterTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.interface = Interface1(self.serial)
+
+        self.interface._execute_offload = Mock()
+
+    def test(self):
+        # Act
+        self.interface.offload_load_address_counter(960)
+
+        # Assert
+        self.interface._execute_offload.assert_called_with(0x01, bytes.fromhex('03 c0'))
+
+class Interface1OffloadWriteTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.interface = Interface1(self.serial)
+
+        self.interface._execute_offload = Mock()
+
+    def test_message_is_sent_with_data(self):
+        # Act
+        self.interface.offload_write(bytes.fromhex('de ad be ef'))
+
+        # Assert
+        self.interface._execute_offload.assert_called_with(0x02, bytes.fromhex('ff ff 00 00 00 de ad be ef'))
+
+    def test_message_is_sent_with_address(self):
+        # Act
+        self.interface.offload_write(bytes.fromhex('de ad be ef'), address=960)
+
+        # Assert
+        self.interface._execute_offload.assert_called_with(0x02, bytes.fromhex('03 c0 00 00 00 de ad be ef'))
+
+    def test_message_is_sent_with_restore_original_address(self):
+        # Act
+        self.interface.offload_write(bytes.fromhex('de ad be ef'), restore_original_address=True)
+
+        # Assert
+        self.interface._execute_offload.assert_called_with(0x02, bytes.fromhex('ff ff 01 00 00 de ad be ef'))
+
+    def test_message_is_sent_with_repeat(self):
+        # Act
+        self.interface.offload_write(bytes.fromhex('de ad be ef'), repeat=1)
+
+        # Assert
+        self.interface._execute_offload.assert_called_with(0x02, bytes.fromhex('ff ff 00 00 01 de ad be ef'))
+
+class Interface1ReadMessageTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.interface = Interface1(self.serial)
+
+        self.interface.slip_serial = Mock()
+
+    def test(self):
+        # Arrange
+        self.interface.slip_serial.recv_msg = Mock(return_value=bytes.fromhex('00 04 01 02 03 04 00 00'))
+
+        # Act
+        message = self.interface._read_message()
+
+        # Assert
+        self.assertEqual(message, bytes.fromhex('01 02 03 04'))
+
+    def test_protocol_error_is_handled_correctly(self):
+        # Arrange
+        self.interface.slip_serial.recv_msg = Mock(side_effect=sliplib.ProtocolError)
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'SLIP protocol error'):
+            self.interface._read_message()
+
+    def test_invalid_message_length_is_handled_correctly(self):
+        # Arrange
+        self.interface.slip_serial.recv_msg = Mock(return_value=bytes.fromhex('00'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Invalid response message'):
+            self.interface._read_message()
+
+    def test_message_length_mismatch_is_handled_correctly(self):
+        # Arrange
+        self.interface.slip_serial.recv_msg = Mock(return_value=bytes.fromhex('00 05 01 02 03 04 00 00'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Response message length mismatch'):
+            self.interface._read_message()
+
+    def test_empty_message_is_handled_correctly(self):
+        # Arrange
+        self.interface.slip_serial.recv_msg = Mock(return_value=bytes.fromhex('00 00 00 00'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Empty response message'):
+            self.interface._read_message()
+
+class Interface1WriteMessageTestCase(unittest.TestCase):
+    def setUp(self):
+        self.serial = Mock()
+
+        self.interface = Interface1(self.serial)
+
+        self.interface.slip_serial = Mock()
+
+    def test(self):
+        # Act
+        self.interface._write_message(bytes.fromhex('01 02 03 04'))
+
+        # Assert
+        self.interface.slip_serial.send_msg.assert_called_with(bytes.fromhex('00 04 01 02 03 04 00 00'))
+
+if __name__ == '__main__':
+    unittest.main()
--- a/pycoax/tests/test_parity.py
+++ b/pycoax/tests/test_parity.py
@@ -0,0 +1,34 @@
+import unittest
+
+import context
+
+from coax.parity import even_parity, odd_parity
+
+class EvenParityTestCase(unittest.TestCase):
+    def test_with_even_input(self):
+        self.assertEqual(even_parity(0b00000000), 0)
+
+    def test_with_odd_input(self):
+        self.assertEqual(even_parity(0b00000001), 1)
+
+    def test_with_out_of_range_input(self):
+        for input in [-1, 256]:
+            with self.subTest(input=input):
+                with self.assertRaises(ValueError):
+                    even_parity(input)
+
+class OddParityTestCase(unittest.TestCase):
+    def test_with_even_input(self):
+        self.assertEqual(odd_parity(0b00000000), 1)
+
+    def test_with_odd_input(self):
+        self.assertEqual(odd_parity(0b00000001), 0)
+
+    def test_with_out_of_range_input(self):
+        for input in [-1, 256]:
+            with self.subTest(input=input):
+                with self.assertRaises(ValueError):
+                    odd_parity(input)
+
+if __name__ == '__main__':
+    unittest.main()
--- a/pycoax/tests/test_protocol.py
+++ b/pycoax/tests/test_protocol.py
@@ -0,0 +1,99 @@
+import unittest
+from unittest.mock import Mock
+
+import context
+
+from coax import PollResponse, KeystrokePollResponse, ProtocolError
+from coax.protocol import Command, _execute_read_command, _execute_write_command, _pack_command_word, _unpack_data_words, _unpack_data_word
+
+class PollResponseTestCase(unittest.TestCase):
+    def test_is_power_on_reset_complete(self):
+        self.assertTrue(PollResponse.is_power_on_reset_complete(0b0000001010))
+
+    def test_is_keystroke(self):
+        self.assertTrue(PollResponse.is_keystroke(0b1111111110))
+
+class KeystrokePollResponseTestCase(unittest.TestCase):
+    def test(self):
+        # Act
+        response = KeystrokePollResponse(0b1111111110)
+
+        # Assert
+        self.assertEqual(response.scan_code, 0xff)
+
+    def test_not_a_keystroke(self):
+        with self.assertRaisesRegex(ValueError, 'Invalid keystroke poll response'):
+            response = KeystrokePollResponse(0b0000001000)
+
+class ExecuteReadCommandTestCase(unittest.TestCase):
+    def setUp(self):
+        self.interface = Mock()
+
+    def test(self):
+        # Arrange
+        self.interface.execute = Mock(return_value=[0b0000000010])
+
+        # Act and assert
+        self.assertEqual(_execute_read_command(self.interface, Command.READ_TERMINAL_ID), bytes.fromhex('00'))
+
+    def test_unexpected_response_length(self):
+        # Arrange
+        self.interface.execute = Mock(return_value=[])
+
+        # Act and assert
+        with self.assertRaisesRegex(ProtocolError, 'Expected 1 word READ_TERMINAL_ID response'):
+            _execute_read_command(self.interface, Command.READ_TERMINAL_ID)
+
+class ExecuteWriteCommandTestCase(unittest.TestCase):
+    def setUp(self):
+        self.interface = Mock()
+
+    def test(self):
+        # Arrange
+        self.interface.execute = Mock(return_value=[0b0000000000])
+
+        # Act and assert
+        _execute_write_command(self.interface, Command.WRITE_DATA, bytes.fromhex('de ad be ef'))
+
+    def test_unexpected_response_length(self):
+        # Arrange
+        self.interface.execute = Mock(return_value=[])
+
+        # Act and assert
+        with self.assertRaisesRegex(ProtocolError, 'Expected 1 word WRITE_DATA response'):
+            _execute_write_command(self.interface, Command.WRITE_DATA, bytes.fromhex('de ad be ef'))
+
+    def test_not_tr_ta_response(self):
+        # Arrange
+        self.interface.execute = Mock(return_value=[0b0000000010])
+
+        # Act and assert
+        with self.assertRaisesRegex(ProtocolError, 'Expected TR/TA response'):
+            _execute_write_command(self.interface, Command.WRITE_DATA, bytes.fromhex('de ad be ef'))
+
+class PackCommandWordTestCase(unittest.TestCase):
+    def test_without_address(self):
+        self.assertEqual(_pack_command_word(Command.POLL_ACK), 0b001000101)
+
+    def test_with_address(self):
+        self.assertEqual(_pack_command_word(Command.POLL_ACK, address=3), 0b111000101)
+
+class UnpackDataWordsTestCase(unittest.TestCase):
+    def test(self):
+        self.assertEqual(_unpack_data_words([0b0000000010, 0b1111111110]), bytes.fromhex('00 ff'))
+
+class UnpackDataWordTestCase(unittest.TestCase):
+    def test(self):
+        self.assertEqual(_unpack_data_word(0b0000000010), 0x00)
+        self.assertEqual(_unpack_data_word(0b1111111110), 0xff)
+
+    def test_data_bit_not_set_error(self):
+        with self.assertRaisesRegex(ProtocolError, 'Word does not have data bit set'):
+            _unpack_data_word(0b0000000011)
+    
+    def test_parity_error(self):
+        with self.assertRaisesRegex(ProtocolError, 'Parity error'):
+            _unpack_data_word(0b0000000000)
+
+if __name__ == '__main__':
+    unittest.main()
				`@@ -0,0 +1 @@`
				`(kicad_pcb (version 4) (host kicad "dummy file") )`