Arduino Powered X10+RFID Controlled Curtain Opener

Yes, to either right of left tip and ground to "barrel". Plug in AUX.
First I tried the scope but couldn't tell much. With the speakers on I could hear when the signal was weak. Later, I put a call to tone() Thomas's example:

// Process commands received from X10 compatible RF remote
void processRfCommand(char house, byte unit, byte command, bool isRepeat)
{
  if(!isRepeat)
  {
    tone1.play(2400,1000); // <---- ADDED THIS
    printX10Message(RADIO_FREQ_MSG, house, unit, command, 0, 0, 0);
  }

Then I could walk around and do some fine tuning by seeing how far I could go and still hear the tone.