[TheList] Seldec-4 & Selcall+

Sat Jul 24 15:07:16 AEST 2010

It isn't quite that simple. The equipment at the comms end is not just a
receiver and decoder. There is a whole lot of processing that goes on. For
example, there is a short delay (about 300ms) built into the system which
allows the selcal tones to be identified and muted so that the dispatcher
does not hear them. When they go digital the whole system will need to be
changed. 

I doubt that they would retain an analogue data system over a digital
network which has the capability for far more sophisticated messaging than
is currently available. If you are going to digitize the voice traffic you
might as well use the system for the data. I would expect that a digital
radio network for fire would include text and data capability, if not a full
MDT system. Analogue signaling is very limited and pretty much obsolete.

Andy

-----Original Message-----
From: thelist-bounces at radiowiki.org.nz
[mailto:thelist-bounces at radiowiki.org.nz] On Behalf Of Gary Lowndes
Sent: Wednesday, 21 July 2010 9:33 p.m.
To: thelist at radiowiki.org.nz
Subject: Re: [TheList] Seldec-4 & Selcall+

> If Fire were to go digital, which they will eventually - but not
encrypted.
> Will the Selcall decoder still work as per on analogue?

The bottom line is that if you can hear the tones then so can the 
decoder, and conversely you can't decode something you can't hear.

So long as the move is a simple radio swap and just replaces the 
existing analogue setup with an identical system using digital radios, 
then it shouldn't make any difference to the decoder.

Gary

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