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Posted: **Sun Jul 21, 2002 9:05 pm**

Our FD uses ASTRO Spectra consolettes at each fire station for individual station call-alerting. These radios are part of an 800MHz Smartnet (non-ASTRO) system, and when activated, they open the station speakers and an external relay turns on the station lights.

My question is this: what kind of signalling is used to alert each individual ASTRO Spectra? Let me narrow it down for you -- they don't use QC-II, MDC, or any audible data sent across a voice ch/talkgroup. I continously monitor the system with Trunker and it does not indicate any TG key-up when each station radio is addressed, so the signalling is obviously sent across the active Control Channel (but not detected/decoded by Trunker). So what other signal-decoding protocols are available on an ASTRO Spectra?

Posted: **Mon Jul 22, 2002 11:52 am**

You are correct, any trunking signalling is done through the control channel. We have a very similar set-up here for our FD's. Analog Spectras at each FD tie into the stations P.A. systems. There's no actual signalling involved with ours, the dispatchers send an audible alert (Hi/Low tones) over the particular FD's talkgroup with their Centracom consoles, then follow up with the voice message. In your case, they are probably using the Trunking Call Alert feature to alert the radio & trip the lights relay. Or perhaps use no signalling & simply use a COS/COR to trip the lights.

Todd

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Signalling question for ASTRO Spectra experts

Signalling question for ASTRO Spectra experts