diff --git a/src/main.cpp b/src/main.cpp
index 800a07b..b654f46 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,24 +1,247 @@
 #include <Arduino.h>
 #include "Keyboard.h"
+#include "EEPROM.h"
 
-#define PIN_BUTTON 12
+#define SERIAL_PORT Serial
 
-String password="echo \"czimage:CC37*#dfk7,A6b3cqKS\" >cred && chmod 600 cred && s3fs clonezilla /home/partimag -o passwd_file=cred,use_path_request_style,url=https://ccsnstorage.catholiccharities.com:9000";
+// configuration
+
+const int slotcount=1; // number of keys to support
+String passwords[slotcount]; // password storage
+int pins[slotcount]={12}; // pins to which keys are attached
+
+// other globals
+
+String command=""; // serial-port command buffer
+const String version="0.1"; // firmware version
+const String hw_version="0.2"; // hardware version
+
+// prototypes
+
+void setup();
+void loop();
+void SendPassword(int slot);
+void LoadPasswords();
+void SavePasswords();
+void Help();
+void ShowPassword(int key);
+void ShowAll();
+void ShowVersion();
+String ReadHWVersion();
+
+// initialization
 
 void setup() 
 {
-  pinMode(PIN_BUTTON, INPUT_PULLUP);
+  SERIAL_PORT.begin(9600);
+  SERIAL_PORT.write(']');
+
+  // set up input pins
+
+  for (int slot=0; slot<slotcount; slot++)
+    pinMode(pins[slot], INPUT_PULLUP);
+
+  // load passwords
+
+  LoadPasswords();
 }
 
+// event loop
+
 void loop() 
 {
-  if (!digitalRead(PIN_BUTTON))
+  char inchr;
+  bool cmdComplete=false;
+
+  // scan keys
+
+  for (int slot=0; slot<slotcount; slot++)
+    if (!digitalRead(pins[slot]))
+      SendPassword(slot);
+
+  // grab serial-port input
+
+  if (SERIAL_PORT.available()>0)
   {
-    for (int i=0; i<password.length(); i++)
+    inchr=SERIAL_PORT.read();
+    if (inchr>=32 && inchr<127) // printable?
     {
-      Keyboard.press(password[i]);
-      Keyboard.releaseAll();
+      command+=inchr;
+      SERIAL_PORT.write(inchr); // echo it back
     }
-    delay(500);
+    if (inchr==8 || inchr==127) // delete or backspace?
+      if (command.length()>0)
+      {
+        command=command.substring(0,command.length()-1);
+        SERIAL_PORT.write(8); // erase last character
+        SERIAL_PORT.write(32);
+        SERIAL_PORT.write(8);
+      }
+    if (inchr==13) // return?
+    {
+      cmdComplete=true; // end of line
+      SERIAL_PORT.write("\r\n");
+    }
+  }
+  if (cmdComplete) // EOL?
+  {
+    if (command=="")
+      Help();
+    else if (command.substring(0,5)=="show ")
+    {
+      command=command.substring(5);
+      if (command=="all")
+        ShowAll();
+      else
+        ShowPassword(command.toInt());
+    }
+    else if (command.substring(0,4)=="set ")
+    {
+      command=command.substring(4);
+      int slot=0;
+      while (command[0]!=' ')
+      {
+        slot=10*slot+String(command[0]).toInt();
+        command=command.substring(1);
+      }
+      command=command.substring(1);
+      if (slot>=0 && slot<slotcount)
+      {
+        passwords[slot]=command;
+        SavePasswords();
+        ShowPassword(slot);
+      }
+      else
+      {
+        SERIAL_PORT.write(7);
+        SERIAL_PORT.println("?RANGE ERROR");
+      }
+    }
+    else if (command=="version")
+    {
+      ShowVersion();
+    }
+    else
+    {
+      SERIAL_PORT.write(7); 
+      SERIAL_PORT.println("?SYNTAX ERROR"); // Apple II-style error messages, because we can :-)
+    }
+
+    command="";
+    SERIAL_PORT.write(']'); // and an Apple II-style prompt, too
   }
 }
+
+void SendPassword(int slot)
+{
+    for (int i=0; i<passwords[slot].length(); i++)
+    {
+      Keyboard.press(passwords[slot][i]);
+      Keyboard.release(passwords[slot][i]);
+    }
+    delay(1000);
+}
+
+// read passwords from EEPROM
+
+void LoadPasswords()
+{
+  int memptr=16;
+  char c;
+  uint32_t magic;
+
+  EEPROM.begin(4096);
+
+  EEPROM.get(0, magic);
+  if (magic==0xDEADBEEF) // initialized?
+    for (int slot=0; slot<slotcount; slot++)
+    {
+      passwords[slot]="";
+      while ((c=EEPROM.read(memptr++))!=0)
+        passwords[slot]+=c;
+    }
+  else // no...initialize it
+  {
+    for (int i=0; i<4096; i++) // erase all
+      EEPROM.write(i, 0);
+
+    magic=0xDEADBEEF; // write magic value
+    EEPROM.put(0, magic);
+
+    memptr=4; // write hardware version string
+    for (int i=0; i<hw_version.length(); i++)
+      EEPROM.write(memptr++, hw_version[i]);
+    EEPROM.write(memptr, 0);
+  }
+
+  EEPROM.end();
+}
+
+// write passwords to EEPROM
+
+void SavePasswords()
+{
+  EEPROM.begin(4096);
+
+  int memptr=16;
+  for (int slot=0; slot<slotcount; slot++)
+  {
+    for (int i=0; i<passwords[slot].length(); i++)
+      EEPROM.write(memptr++,passwords[slot][i]);
+    EEPROM.write(memptr++,0);
+  }
+
+  EEPROM.end();
+}
+
+// display help on an empty input
+
+void Help()
+{
+  SERIAL_PORT.println("Help\r\n====\r\n");
+  SERIAL_PORT.println("set n data    set password for key n to data");
+  SERIAL_PORT.println("show n        show password for key n");
+  SERIAL_PORT.println("show all      show all passwords");
+  SERIAL_PORT.println("version       show hardware & firmware information\r\n");
+  SERIAL_PORT.println("(n starts at 0 and goes to one less than the total");
+  SERIAL_PORT.println("number of keys\r\n");
+}
+
+void ShowPassword(int key)
+{
+  if (key>=0 && key<slotcount)
+    SERIAL_PORT.println("pwd "+String(key)+": "+passwords[key]);
+  else
+  {
+    SERIAL_PORT.write(7);
+    SERIAL_PORT.println("?RANGE ERROR");
+  }
+}
+
+void ShowAll()
+{
+  for (int i=0; i<slotcount; i++)
+    ShowPassword(i);
+}
+
+void ShowVersion()
+{
+  SERIAL_PORT.println("Firmware version: "+version);
+  SERIAL_PORT.println("Hardware version: "+ReadHWVersion());
+  SERIAL_PORT.println("Total keys configured: "+String(slotcount));
+}
+
+String ReadHWVersion()
+{
+  int memptr=4;
+  char c;
+  String version="";
+
+  EEPROM.begin(4096);
+
+  while ((c=EEPROM.read(memptr++))!=0)
+    version+=c;
+  return version;
+
+  EEPROM.end();
+}