diff --git a/webUI/B5500SPOUnit.html b/webUI/B5500SPOUnit.html
index 6a6c324..f8d9d9b 100644
--- a/webUI/B5500SPOUnit.html
+++ b/webUI/B5500SPOUnit.html
@@ -7,8 +7,6 @@
 <meta http-equiv="Content-Style-Type" content="text/css">
 <link id=defaultStyleSheet rel=stylesheet type="text/css" href="B5500SPOUnit.css">
 
-<script src="../emulator/B5500IOUnit.js"></script>
-
 <script>
 
 window.onload = function() {
@@ -33,6 +31,16 @@ window.onload = function() {
         nextCharTime:   0,
         finished:       null};
         
+    var keyFilter = [               // Filter keyCode values to valid B5500 ones
+        0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,  // 00-0F
+        0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,0x3F,  // 10-1F
+        0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x3F,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,  // 20-2F
+        0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,  // 30-3F
+        0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,  // 40-4F
+        0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x5B,0x3F,0x5D,0x3F,0x3F,  // 50-5F
+        0x3F,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,  // 60-6F
+        0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x3F]; // 70-7F
+        
     var hasClass = function(e, name) {
         /* returns true if element "e" has class "name" in its class list */
         var classes = e.className;
@@ -63,8 +71,10 @@ window.onload = function() {
     var addFrameStyles = function(frame) {
         /* Appends the necessary styles for the <iframe> to its internal stylesheet */
         
-        frame.contentDocument.head.innerHTML += "<style>BODY {background-color: #FFE} " +
-                "PRE {margin: 0; font-size: 10pt; font-family: Lucida Sans Typewriter, Courier New, Courier, monospace}";
+        frame.contentDocument.head.innerHTML += "<style>" +
+                "BODY {background-color: #FFE} " +
+                "PRE {margin: 0; font-size: 10pt; font-family: Lucida Sans Typewriter, Courier New, Courier, monospace}" +
+                "</style>";
     };
     
     var appendEmptyLine = function(count) {
@@ -111,17 +121,21 @@ window.onload = function() {
         }
     };
     
-    var echoChar = function(index) {
-        /* Echos msgCtl.buffer[index] to the SPO printer. Used by keyboard input */
+    var echoChar = function(c) {
+        /* Echoes the character code "c" to the SPO printer. Used by keyboard input */
         var body = $$("SPOUT").contentDocument.body;
         var line = body.lastChild.lastChild;
-        var c = String.fromCharCode(msgCtl.buffer[index]);
         
-        msgCtl.index = index+1;
-        if (index < 71) {
-            line.nodeValue += c;
+        if (c == 8) {
+            if (line.nodeValue.length > 0) {
+                line.nodeValue = line.nodeValue.substring(-1);
+            }
+        } else if (c == 13) {
+            appendEmptyLine(1);
+        } else if (line.nodeValue.length < 72) {
+            line.nodeValue += String.fromCharCode(c);
         } else {
-             line.nodeValue = line.nodeValue.substring(0,71) + c;
+             line.nodeValue = line.nodeValue.substring(0,71) + String.fromCharCode(c);
         }
    };
 
@@ -237,7 +251,7 @@ window.onload = function() {
         if (spoState == spoRemote) {
             accept();
         } else if (spoState == spoOutput) {
-            inputRequested = True;
+            inputRequested = true;
         }
     };
     
@@ -295,7 +309,7 @@ window.onload = function() {
         
         printText("*** B5500 SPO TEST ***");
         printText(" ");
-        printText("WHAT HATH BARTON WROUGHT?");
+        printText("WHAT HATH PASADENA WROUGHT?");
         printText("");
         /*****
         printText("123456789.123456789.123456789.123456789.123456789.123456789.123456789.1");
@@ -341,47 +355,70 @@ window.onload = function() {
     
     window.onkeypress = function(ev) {
         var c = ev.charCode;
-        var stamp = new Date().getTime();
-        var nextTime;
         var index = msgCtl.length;
+        var nextTime;
+        var result = false;
+        var stamp = new Date().getTime();
         
+        if (msgCtl.nextCharTime > stamp) {
+            nextTime = msgCtl.nextCharTime + 100;
+        } else {
+            nextTime = stamp + 100;
+        }
+        msgCtl.nextCharTime = nextTime;
         if (spoState == spoInput) {
             if (c >= 32 && c <= 126) {
-                c = B5500IOUnit.BICtoANSI[B5500IOUnit.ANSItoBIC[c]];
-                msgCtl.buffer[index] = c.charCodeAt(0);
+                msgCtl.buffer[index] = c = keyFilter[c & 0x7F];
                 if (msgCtl.length < 72) {
                     msgCtl.col++;
                     msgCtl.length++;
+                    msgCtl.index++;
                 }
-                if (msgCtl.nextCharTime > stamp) {
-                    nextTime = msgCtl.nextCharTime + 100;
-                } else {
-                    nextTime = stamp + 100;
-                }
-                msgCtl.nextCharTime = nextTime;
-                setTimeout(function() {echoChar(index)}, nextTime-stamp);
+                setTimeout(function() {echoChar(c)}, nextTime-stamp);
+            }
+        } else if (spoState == spoLocal) {
+            if (c >= 32 && c <= 126) {
+                c = keyFilter[c & 0x7F];
+                setTimeout(function() {echoChar(c)}, nextTime-stamp);
             }
         }
+        return result;
     };
     
     window.onkeydown = function(ev) {
+        var c = ev.keyCode;
+        var result = false;
+        
         if (spoState == spoRemote) {
-            if (ev.keyCode == 27) {
+            if (c == 27) {
                 initiateInput(ev);
             }
         } else if (spoState == spoInput) {
-            switch (ev.keyCode) {
-            case 27:
+            switch (c) {
+            case 27:                    // ESC
                 cancelInput(ev);
                 break;
-            case 8:
+            case 8:                     // Backspace
                 backspaceChar();
                 break;
-            case 13:
+            case 13:                    // Enter
+            case 126:                   // "~" (B5500 left arrow/group mark)
                 terminateInput(ev);
                 break;
+            default:
+                result = true;
+            }
+        } else if (spoState == spoLocal) {
+            switch (c) {
+            case 8:                     // Backspace
+            case 13:                    // Enter
+                echoChar(c);
+                break;
+            default:
+                result = true;
             }
         }
+        return result;
     };
     
     addFrameStyles($$("SPOUT"));