Data as FSK

I have a perfectly running Asterisk, running on CentOS, in the end of a sip trunk. Now I received a request, that I should receive and handle FSK data. As in, there are home security panels, that send data with SIA-FSK-format and I’d like to parse the that is data sent in and check if the data is valid or not.

I’ve noticed, that FSK can be used when receiving caller id, but can Asterisk parse other data as well, or should I just create a listener/parser of my own…?


  1. There is an alarmreceiver application that may or may not handle the protocol that you are using.

  2. The FSK demodulation in Asterisk is not very good. Unless it has changed recently, it uses the same sort of logic as used for DTMF, which is only really suited to baud rates much lower than the carrier frequency.

  3. I suspect this may be better pursued as as developer question.

  1. Alarmreceiver works with ContactID alarm transmission format, which is dtmf. SIA is quite a bit different, although used for same thing.

  2. Darn.

  3. Might be, I think I’ll ask from there too…

Thanks a lot for your answer.