diff --git a/interface1/firmware/src/main.cpp b/interface1/firmware/src/main.cpp
index 260db2a..5d025b7 100644
--- a/interface1/firmware/src/main.cpp
+++ b/interface1/firmware/src/main.cpp
@@ -64,11 +64,18 @@ void sendMessage(uint8_t *buffer, int bufferCount)
     Serial.flush();
 }
 
-void sendErrorMessage(uint8_t code)
+void sendErrorMessage(uint8_t code, const char *description)
 {
-    uint8_t message[] = { 0x02, code };
+    uint8_t message[2 + 62 + 1] = { 0x02, code };
+    int count = 2;
 
-    sendMessage(message, 2);
+    if (description != NULL) {
+        strncpy((char *) (message + 2), description, 62);
+
+        count += strlen(description);
+    }
+
+    sendMessage(message, count);
 }
 
 #define COMMAND_RESET 0x01
@@ -86,7 +93,7 @@ void handleResetCommand(uint8_t *buffer, int bufferCount)
 void handleTransmitReceiveCommand(uint8_t *buffer, int bufferCount)
 {
     if (bufferCount < 6) {
-        sendErrorMessage(ERROR_INVALID_MESSAGE);
+        sendErrorMessage(ERROR_INVALID_MESSAGE, "HANDLE_TXRX_BUFFER_COUNT_6");
         return;
     }
 
@@ -100,7 +107,7 @@ void handleTransmitReceiveCommand(uint8_t *buffer, int bufferCount)
     uint16_t receiveTimeout = (buffer[bufferCount - 2] << 8) | buffer[bufferCount - 1];
 
     if (transmitBufferCount < 1) {
-        sendErrorMessage(ERROR_INVALID_MESSAGE);
+        sendErrorMessage(ERROR_INVALID_MESSAGE, "HANDLE_TXRX_TX_BUFFER_COUNT_1");
         return;
     }
 
@@ -127,7 +134,7 @@ void handleTransmitReceiveCommand(uint8_t *buffer, int bufferCount)
     bufferCount = CoaxTransceiver::transmitReceive(transmitBuffer, transmitBufferCount, receiveBuffer, receiveBufferSize, receiveTimeout);
 
     if (bufferCount < 0) {
-        sendErrorMessage(100 + ((-1) * bufferCount));
+        sendErrorMessage(100 + ((-1) * bufferCount), NULL);
         return;
     }
 
@@ -142,7 +149,7 @@ void handleTransmitReceiveCommand(uint8_t *buffer, int bufferCount)
 void handleMessage(uint8_t *buffer, int bufferCount)
 {
     if (bufferCount < 1) {
-        sendErrorMessage(ERROR_INVALID_MESSAGE);
+        sendErrorMessage(ERROR_INVALID_MESSAGE, "HANDLE_MESSAGE_BUFFER_COUNT_1");
         return;
     }
 
@@ -153,21 +160,21 @@ void handleMessage(uint8_t *buffer, int bufferCount)
     } else if (command == COMMAND_TRANSMIT_RECEIVE) {
         handleTransmitReceiveCommand(buffer + 1, bufferCount - 1);
     } else {
-        sendErrorMessage(ERROR_UNKNOWN_COMMAND);
+        sendErrorMessage(ERROR_UNKNOWN_COMMAND, NULL);
     }
 }
 
 void handleFrame(uint8_t *buffer, int bufferCount)
 {
     if (bufferCount < 4) {
-        sendErrorMessage(ERROR_INVALID_MESSAGE);
+        sendErrorMessage(ERROR_INVALID_MESSAGE, "HANDLE_FRAME_BUFFER_COUNT_4");
         return;
     }
 
     int count = (buffer[0] << 8) | buffer[1];
 
     if (bufferCount - 4 != count) {
-        sendErrorMessage(ERROR_INVALID_MESSAGE);
+        sendErrorMessage(ERROR_INVALID_MESSAGE, "HANDLE_FRAME_BUFFER_COUNT_MISMATCH");
         return;
     }
 
diff --git a/pycoax/coax/serial_interface.py b/pycoax/coax/serial_interface.py
index b632507..e6fb501 100644
--- a/pycoax/coax/serial_interface.py
+++ b/pycoax/coax/serial_interface.py
@@ -162,7 +162,18 @@ def _convert_error(message):
         return InterfaceError(f'Invalid error response: {message}')
 
     if message[1] in ERROR_MAP:
-        return ERROR_MAP[message[1]]
+        error = ERROR_MAP[message[1]]
+
+        # Append description if included.
+        if len(message) > 2:
+            description = message[2:].decode('ascii')
+
+            if error.args:
+                error.args = (f'{error.args[0]}: {description}', *error.args[1:])
+            else:
+                error.args = (description,)
+
+        return error
 
     return InterfaceError(f'Unknown error: {message[1]}')
 
diff --git a/pycoax/tests/test_serial_interface.py b/pycoax/tests/test_serial_interface.py
index 56ded69..dbb7a87 100644
--- a/pycoax/tests/test_serial_interface.py
+++ b/pycoax/tests/test_serial_interface.py
@@ -53,6 +53,14 @@ class SerialInterfaceResetTestCase(unittest.TestCase):
         with self.assertRaisesRegex(InterfaceError, 'Invalid request message'):
             self.interface.reset()
 
+    def test_error_with_description_is_handled_correctly(self):
+        # Arrange
+        self.interface._read_message = Mock(return_value=bytes.fromhex('02 01 45 72 72 6f 72 20 64 65 73 63 72 69 70 74 69 6f 6e'))
+
+        # Act and assert
+        with self.assertRaisesRegex(InterfaceError, 'Invalid request message: Error description'):
+            self.interface.reset()
+
 # TODO...
 
 class SerialInterfaceReadMessageTestCase(unittest.TestCase):