i'm a little new in this. I have an alarm system panel which has TX,RX wires with 12V output/input.

how can i read the output with arduino and control it with serial communication?

1 Answer 1


First of all, you'll need to make sure this is UART and not another protocol. Don't worry, if it's not UART the worst thing that could happen is jumbled data.

After that, you will need a 12v to 5v (or 3.3v) logic level shifter. When you have that you'll need to connect the Arduino to the system through the level shifter to pins 0/1.

You won't know what you'll receive or can send without looking at the serial output and doing a little tinkering. You don't even know what the serial port does. It could just be for setting up the system.

  • what is logic level shifter? cant i ues simple voltage divider ?
    – Noris S
    Sep 15, 2014 at 9:29
  • @NorisS you could from the system to the Arduino but you need a way to increase the signal for the receiving line on the system. A logic level shifter just translates voltages. Sep 15, 2014 at 12:22
  • can you recommend me specific model?
    – Noris S
    Sep 15, 2014 at 13:15
  • @Nor my phone isn't loading the datasheet but comments seem to say that this will work: sparkfun.com/products/12009 remember to use a common ground. Sep 15, 2014 at 13:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.