[op25-dev] Why can't I hear fire tones?

'William Becks' wllmbecks@gmail.com [op25-dev] op25-dev at yahoogroups.com
Sat Jun 16 20:19:55 UTC 2018

What exactly are you trying to determine about the tones?   They appear to be “Alert” tones sent by the dispatch operator ahead of the voice message.  I don’t think they actually serve as a signaling function as would commonly be found in analog paging systems.  


I believe that someone has already stated that there are only a handful of specific tones or tone combinations that are provided for in the P25 vocoder.  Any other tones or tone combinations transmitted into the speech input of the vocoder quote likely will not reproduce and exact replica as the source tone(s) primarily because the vocoder is designed to encode and compress speech.

Bill, WA8WG






From: op25-dev at yahoogroups.com [mailto:op25-dev at yahoogroups.com] 
Sent: Saturday, June 16, 2018 2:58 PM
To: op25-dev at yahoogroups.com
Subject: RE: [op25-dev] Re: Why can't I hear fire tones?



Here are the fire tones I hear on a Uniden Scanner. I am not sure if it actually goes to a separate frequency just for the tones, but to me it doesn't sound like it. https://soundcloud.com/nokoa-official/sets/fire-tones

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