Can anyone identify this trunked system call sign?

[temfreqhunter]

3F3 is the call sign. My scanner says that it is a P25 system. 100% encrypted.

[brandon]

3F3 isn't a typical callsign used in the USA so I am betting this is the NAC code for the P25 traffic you heard. What frequency was this?
The DHS and other three letter agencies have many P25 encrypted repeaters in the ~163-174 MHz range.

[temfreqhunter]

The frequency, which I think is trunked, is 856.2125.

[brandon]

Hello. That freq is part of the Orange County TRS Countywide Cell
Here is a complete listing for the system: http://www.radioreference.com/apps/db/?sid=201
SysID: 6c3f

[temfreqhunter]

I checked that, but the sysID's do not match. Orange county, like you said is 6c3f, but the one I found was 3f3

[zz0468]

Likely part of the OC system, but it's also licensed to the City of LA.