Originally Posted By radioshooter:
Don't confuse P25 with digital voice.
I am a lowly scanner user, but I am sure P25 is digital voice because it has a specified vocoder, but not all digital voice systems are P25. Are you saying that not all trunk systems are digital which is correct.
All P25 systems are digital.
Not all digital systems are P25.
You have a protocol, Ie P25, and a vocoder (voice encoder/decoder).
P25 can be phase 1 (FDMA) or Phase 2 (TDMA).
APCO P25 is a PROTOCOL to meet the standards of APCO Project 25. It in of itself is NOT digital voice.
You can run conventional with digital (IMBE) audio that's NOT P25. You can run a 3600 baud smartzone system with digital audio (IMBE) that's NOT P25.
Most people think that any digital audio is P25, it's not.
A 3600 baud smartzone system with IMBE (DIGITAL) voice is NOT P25, even though people will almost always call it a P25 system since it has digital voice.
Likewise, they assume a radio can 'Do P25' just because it can do digital voice.
In his case, his radio won't do ANY trunking whatsoever, hence the H35 (conventional only) option. But it's a non-issue, since VHF trunked systems are few and far between.