This APCO P25 Decoder Plug-in makes it possible to receive and listen to
digital APCO P25 channels on WiNRADiO WR-G39DDC Series receivers.
APCO Project 25 (P25) was developed by joint efforts of the Association
of Public Safety Communications Officials International (APCO),
the National Association of State Telecommunications Directors (NASTD),
several US Federal Agencies and the National Communications System
(NCS). It was established to address the need for common digital public
safety radio communications standards for public safety, homeland
security and emergency response.
APCO P25 digital communications offer numerous advantages over analog ones, such as much clearer received audio,
separation of services (fire, homeland security, maintenance, etc.) into coded "talkgroups", individual radio identification
numbering and tracking, GPS location, digital messaging, etc.
For this project, WiNRADiO licensed the IMBE (Improved Multi Band Excitation) vocoder from Digital Voice Systems, Inc. (DVSI)
and combined it with WiNRADiO proprietary software to provide a complete P25 demodulator/decoder for
Compared to the APCO P25 decoder for the low-cost WR-G305 models, the WR-G39DDC version offers a significant number of enhancements:
Logging of APCO signal paramaters
Squelch function based on APCO parameters
Manufacturer's ID indication
Indication of a greater number of encryption types
The APCO P25 Decoder is an XRS Plug-in which, upon installation, can be selected from the receiver's
Plugins -> Decoders top bar menu, as simply another alternative demodulator. The APCO P25
Decoder then appears as an additional window:
The APCO P25 Decoder window consists of the following main parts:
Analyzer panel, which shows the type of received signal and its parameters
Squelch panel, which makes it possible to restrict reception to particular P25 users or groups
Logging panel, which makes it possible to configure logging parameters
The APCO P25 Analyzer panel makes it possible to determine whether the
incoming signal is APCO and analyze its parameters.
There is also an automatic switching facility which makes it possible
for the receiver to stay tuned on a mixed analog/digital channel and the
switching between standard FM demodulation and APCO P25 digital decoding is
performed automatically. The Analyzer will also determine the type of
received digital signal (voice, data or trunking control channel),
whether any encryption is being used and what type of encryption it is.
(However, it will not actually decode encrypted signals.) The signal BER
(Bit Error Rate) is also measured and displayed, making it possible to
assess the quality of the received signal.
The APCO P25 Digital Squelch panel makes it possible to set the numerous
digital parameters available in an APCO P25 transmission to filter out
unwanted transmissions and target only one particular user
or a user group. This is accomplished using APCO P25 specific digital
codes, such as the NAC (Network Access Code), SID (System
TGID (Talk Group Identification), etc. The digital squelch can also
control the recorder, so that only the desired communication of a
particular talkgroup or individual user is being recorded.
2 GHz, quad core
Windows XP, Vista, 7 or 8
WiNRADiO WR-G39DDCe or
Order your APCO P25 decoder via our direct download secure server and you can enjoy it within minutes!