I have been searching the web for a radio or set of radios that would suit my needs. I would like a radio that could monitor a repeater channel but remain silent until "something" activates it or breaks its squelch. I understand that it is what PL tones do, but repeaters already have an input and output set. So, I wonder if any radios allow for 2 different PL tones to be input simultaneously?
I know that most gmrs radios seem to have DTMF capability to send, but they generally do not decode or make use of them on the receiving side.
Once the radio wakes up, I don't mind if all repeater traffic comes across it, but in my situation, I would like for it to sit silently until it is "activated" or called.
The receiving radio does not need to be a GMRS radio, as it only has to alert that a family member is trying to make contact. It could be a HAM radio or scanner. At that point, the contact can turn on a GMRS radio to complete the contact.
I realize that the audio from a HT could probably be piped into an Arduino or a Raspberry Pi, and a DTMF decoder could be programmed to trigger an alarm, but I am guessing there are probably radios that have this functionality.
Any info would be greatly appreciated.