It's about time something was written about operating in P25 mode on the repeater net. So what is it?
Well, APCO 25, abbreviated simply P25 is a digital voice standard for 2-way radio communications. For a primer, read the Wikipedia Page
In the context of amateur radio repeaters, P25 is one of at least a few standards being used for digital voice....as of this writing, other available standards include DMR/Mototrbo, Yaesu System Fusion, Icom D-Star, and NXDN
"DIGITAL DIVERGENCE" is my term of endearment for these incompatible variety of standards. So, which one to pick? XOnet decided on going with the P25 standard because of its wide adoption in public safety systems and easily available top-tier surplus equipment. The drawback to this surplus equipment is that it's not IP network capable out-of-the-box. Because it was developed in the very early 90s, it was designed to use dedicated telco circuits for interconnection instead of the now widely available Internet Protocol. There are technical work arounds available which can run the serial data streams from the repeaters over IP. While XOnet has its own repeaters interconnected by mostly traditional dedicated circuits to a central comparator, our system is connected to other systems via a server running software developed by another ham. This server connects XOnet to other P25 repeaters throughout the world including New Zealand, Australia, Germany, France, Switzerland and of course numerous states within the US. You can see recent transmissions and some stats at P25NX.com
To manage the interconnection on the server, Talkgroups are used to control where the transmissions go. While the talkgroup control is still very much a work in progress, you won't be able to talk outside the XOnet system unless talkgroups are programmed into your radio. The default TGs of 1 and 2 will not transmit outside of XOnet.
With that being said, the talkgroup plan for the P25 interconnection system is:.
1 - Default, Statewide
2 - Default, Statewide
808 - Statewide
10100 - Worldwide
10101 - WW Tac 1
10102 - WW Tac 2
10103 - WW Tac 3
10200 - North America
10300 - Europe
10400 - Pacific
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Last Updated April 12, 2016