dPMR

dPMR (digital Private Mobile Radio) is an open ETSI standard published under the references TS 102 490 (License-free) and TS 102 658 (Licensed). It uses FDMA technology with a channel spacing of 6.25 kHz and supports voice and data applications. The modulation scheme is 4FSK with a bit rate of 4800 bps.

Parameter

Value

Frequency range

Unlicensed: ETSI TS 102 490

446.100 - 446.200 MHz (CEPT ECC/DEC/(05)12)

149.01875 - 149.11875 MHz

Licensed: ETSI TS 102 658

Licensed PMR frequency bands

Operation modes

FDMA, digital voice and data system

Modulation

4FSK (constant envelope FSK)

Symbol rate

2400 Bd

Receiver settings

BW  6.25 kHz

Input format(s)

IF

Additional Info

Voice codec: AMBE+2 (3600 bps)

Bit rate: 4800 bps

Supported Modes

Ø dPMR446

Ø dPMR Mode 1

Ø dPMR Mode 2

TS 102 490 covers only license-free hand portable equipment operating in peer-to-peer mode. The radios should have an integral antenna and are limited in their output power. The standard is also called as dPMR446.

TS 102 658 uses the same air interface technology as in dPMR446 without the limitations of the license-free counterpart. It supports different levels of functionality as listed below.

Ø Mode 1: Peer-to-peer direct network

Ø Mode 2: Conventional repeater network

Ø Mode 3: Managed centralized network

The current version of the dPMR decoder supports the Modes 1 and 2 as well as the license-free dPMR446 operation.

To use the mode set Offset to the IF output of the receiver. Decoded voice will be saved in a “.wav” file in the default Data-Output directory. Use the Mute button to mute or un-mute live voice output to the speaker. The input bits to the vocoder are saved in Hex in a separate file alongside the .wav file. This feature is useful when the voice session is encrypted. The user can analyze and try to decrypt the bits.

In the menu “Option -> Message Type” user can set decoder output to “Data & Voice Frames” or “Bit Transparent”. With “Bit Transparent” option the frames are just output in bits and no protocol decoding is made. This may be useful when the frames are coded in another way than according to the ETSI standard.