VHF and UHF fire and ambulance
Two-tone paging
The pair of tones that opens a fire or ambulance pager, named from an operator list so a call reads as a station rather than two frequencies.
Before any of the digital standards, and still in daily use, a volunteer fire pager is opened by two audio tones in sequence: a long one and a short one, at frequencies unique to that station. Hearing the pair is knowing which crew was just toned out.
WaveShark measures the pair and looks it up in a list you provide, so the alert appears with a name. The voice dispatch that follows the tones is a call on the same channel, recorded and transcribed like any other.
What comes out
- The two tone frequencies and their durations
- The station name, from your own list
- The time of the alert, and the channel
$ waveshark --tune 154.265 --mode nfm --callsRead next
Something did not decode?
Record the burst with --record and open an issue with the capture. A capture that decodes becomes a test fixture.
Open an issue