3 ms·

I recall reading somewhere (IIRC it was a Motorola patented method? Probably expired by this point) that one brand / com method involved a stead, slow / long s

I recall reading somewhere (IIRC it was a Motorola patented method? Probably expired by this point) that one brand / com method involved a stead, slow / long sequence at the start of the analog signal expressly as _the_ thing that terminals woke up on, started to process on, and then could go back to sleep right away if it wasn't a device match.

FireBeyond 3y ago
"Selective calling" - or selcall. It's still very very very widely used in Fire and EMS - listen to any scanner and you'll hear "tones" "dropping" before any dispatch. Motorola Quik-Call is most common around here (there's a sample at this page called 'Tone and voice paging example') - https://en.wikipedia.org/wiki/Selective_calling https://en.wikipedia.org/wiki/Selective_calling In my area, by and large (smaller volunteer departments might just have a 'department' tone), each dispatchable unit has a unique tone (usually two separate tones) and the pager is programmed with a decoder, "if I hear X Hz for x ms, followed by Y Hz for y ms...". Then we will have 'utility' tones, that may not dispatch a unit, but provide information. For example, here a medical call is likely toned as: [engine tone] [generic tone for private ambulance company] [ems utility tone] so you'll get a stream of six tones (well, the utility tones have slightly different rules, so our EMS tone is "beep beep beep" while our Fire tone is "hilo hilo hilo".
- PaulDavisThe1st 3y ago
  There can be problems with the current hybrid state of things, though. Here in my county, dispatch is supposed to use the new phone app method AND tone notifications so that Ye Olde Radios still work. But they don't always remember to do both ...