   case 'P': doTransfer(gt1File);              break;
   case 'U': doTransfer(NULL);                 break;
   case '.': doLine(&line[1]);                 break;
+  case 'C': doEcho(!echo);                    break;
   case 'T': doTerminal();                     break;
   case 'W': sendController(~buttonUp,     2); break;
   case 'A': sendController(~buttonLeft,   2); break;

void doVersion()
{
  #if hasSerial
    Serial.println(":BabelFish [" version "]\n"
                   ":Type 'H' for help");
  #endif
}

void doHelp()

{
  #if hasSerial
    Serial.println(detectGigatron() ? ":Gigatron OK" : "!Gigatron offline");
    Serial.println("Cmd?");
  #endif
}

