Question....

[jwood]

:?:


Now, APCO-25 is "ONLY" a 9600 baud Data Channel correct ???
at least by the APCO-25 WebSite it clearly states that APCO Project 25 is
a system that is using the following below

the FDMA access method
QPSK-C modulation
9.6 data rate
the DVSI vocoder, using a 12.5 KHZ channel.

Now, I see that my Counties System is listed as a APCO-25 Standard System as well as the Ohio Marcs and many many others that are running 3600 baud control channel.

But from what I can see and understand these are not APCO-25 Systems?
3600 Baud Control Channel Systems are APCO-16 as stated on the APCO WebSite...

I am just curious about what I am missing here....

 

[INDY72]

APCO-P-25 is a system of protocols for using digital voice on both trunking and conventional radio systems. Yes a "true" P-25 TRS is using 9600 kbps on the cc and pure digital voice modulation. But also remember that any system using the "P-25 Common Air Interface" for digital voice technically qualifies as a P-25 compatable system. (Motorola ASTRO for example is 3600 kbps but uses the CAI protocols that qualify it as P-25 compatable, where as the Motorola ASTRO-25 format is "true" P-25, both in its trunking format, and in conventional. And the current M/A-Com EDACS Provoice format does not qualify except it uses 9600 kbps CC's...)

The P-25 open protocols call for the IMBE CAI, and usage of iether C4FM, or CQPSK in Phase I.

Remember the data rate only applies to Trunking, and P-25 is not just for Trunking.. It covers conventional as well.