ScanDiego.com

I was wondering if anyone knew what these tones are for, they are played before the dispatch tone. Thanks

http://home.san.rr.com/jms1974/SDFD%20Tone%201.wav

http://home.san.rr.com/jms1974/SDFD%20Tone%202.wav

Could be wrong, but I believe it's for station alerting.

i'm sure tim will answer

They're DTMF, or Dual Tone Multi Frequency tones used to activate the backup station alerting system. Usually at some time before you hear the DTMF usage, you will have heard, "All stations monitor 7A and 7B..." In other words, the link to the primary station alerting is down.

The Fish has it right, although I never hear the tones on my BC246T, Used to hear them on VHF back in the day, though.

N6766J wrote:The Fish has it right, although I never hear the tones on my BC246T, Used to hear them on VHF back in the day, though.

You can always hear them on my first generation trunk scanner, the BC-235. It was always a heads up for a first alarm dispatch... counting the number of tone outs... But in the later scanner generations, they were (properly according to the Motorola trunk protocol) muted...

w6pix wrote: It was always a heads up for a first alarm dispatch... counting the number of tone outs...

OK, this is dating myself, but I can recall hearing the old Motorola tones and knowing if it was a fire by the fact that the last tone is always a bit longer than the rest. If the last tone of the second set of tones was longer, two units.. medical aid. If the last tone of the second set was the same length, then more units were going...

For that matter, I can still pick out our tones from when I was a vollie back east some two decades ago...

When I got my first scanner (1987) I can remember learning the tones, even for a medical aid. E17/M317 and E33/M133 were the easiest for me to discern.