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WHAT IS P25 Phase 2?

What you need to know about P25 Phase 2 and scanning

The new Project 25 Phase 2 modulation mode was created to increase the capacity of digital trunking systems, among other things.  Phase 2 uses a modulation mode called TDMA (Time Division Multiple Access). Motorola uses this mode in their MotoTRBO radios, and Kenwood has a similar mode called NXDN.

Which systems are, or will be Phase 2?

  • Aurora has replaced their previous EDACS system with a 100% P25 Phase 2 system.
  • Lakewood/West Metro Fire/Wheat Ridge (capable, not yet used)
  • Arvada (capable, occasional use) (police are also encrypted, which cannot be monitored)
  • Westminster (capable, not yet used) (police are encrypted, which cannot be monitored)
  • Thornton (capable, not yet used) (police are encrypted, which cannot be monitored)
  • Denver is currently testing a P25 trunk system, which is probably Phase 2 capable, although Phase 2 transmissions have not yet been noted.  This P25 system will eventually replace their current EDACS system. It may also be encrypted when Denver PD moves to this system.
  • The State of Colorado Digital Trunked Radio System (DTRS) is currently Phase 1, and would require major equipment replacement, both at transmitter sites and with field mobiles and handhelds, to convert to Phase 2.  Therefore the DTRS will probably remain Phase 1, at least for the near future.
  • Police systems in RED are now encrypted and not monitorable!

In order to change to Phase 2, both the repeaters and field units must be Phase 2 capable.

How does Phase 2 affect me?

In the future, more systems may begin using Phase 2.  Only the newer scanners will receive Phase 2.  Scanners which are not Phase 2 capable will not receive any trunking talkgroup which uses Phase 2. 


If a talkgroup is Phase 2, but one or more of the users on the talkgroup are not Phase 2 capable, the talkgroup will revert to Phase 1, which you can then receive.  But if the talkgroup is Phase 2, AND all of the users on that talkgroup are Phase 2, the talkgroup will be in Phase 2 mode, and your non-Phase 2 scanner will not receive it.

Which scanners will receive Phase 2 (and also Phase 1)?

Uniden BCD-436HP handheld (an excellent radio)

Uniden BCD-536HP base/mobile (also excellent)

Uniden BCD-325P2 handheld (very good, replaces the BCD-396XT)

Uniden BCD-996P2 base/mobile (very good)


Uniden Home Patrol 2 (very good)

Radio Shack PRO-668 handheld (very good)


Whistler WS-1080, WS-1088, WS-1095, WS-1098, TRX-1, TRX-2


GRE PSR-800 with firmware upgrade


Radio Shack PRO-668


Uniden and Whistler scanners are available in Denver from

Ham Radio Outlet. 

HRO is at 8400 E. Iliff Ave, east of Evans and Quebec,

phone 303 745-7373.


  8400 E. Iliff Av Denver CO 80231
Driving Directions
Click the map to open an interactive map in a new window.

Radio Shack scanners are available at most of the remaining stores.

More technical information on Phase 2 (Provided by Tait)