TTC Radio Data With SDR Receiver

[SCPD]

Does anyone have any information or insight they can share with regard to using a SDR dongle to receive data being transmitted on TTC frequencies (particularly the CIS data channel 423.7375?). Myself and a friend are looking into this using a SDR software but he thinks that the radio data output will likely be garbled nonsense that would require a custom SDR software.

Once again, if anyone can give some advice on this if you are able to, that would be appreciated. I know that it is possible to parse radio data - especially those like air traffic control or any other unencrypted frequencies, but the structure of the data and how it would be parsed is what I am confused about.

Thanks.

 

[gary123]

I would start at looking at the packets as ascii based data. if that fails then you have to look at several complete data packets and look for similarities. Sometimes listening to the input will let you capture a few packets from just one unit.

 

[HiVolt]

You're kind of wasting your time, since this system is being phased out, and the Bus CIS system being first I think.

 

[SCPD]

You're kind of wasting your time, since this system is being phased out, and the Bus CIS system being first I think.

Actually I believe the CIS system is to be phased out last. I saw an internal brochure on the new CAD/AVL system which claims it should be fully implemented around the end of next year.

It may still be possible to monitor communications even on TETRA as they still plan to use existing radio facilities, with LTE cellular as a backup - this is essentially a very similar functionality that they currently have, but with more abilities and fully IP-based.