DMR, or Digital Mobile Radio, is explained in more detail, via my amateur radio section, but for the scanner section a more simplistic explanation follows.

DMR Tier I

DMR Tier I products are for license-free use in the 446 MHz band in the European Union.

This part of the standard provides for consumer applications and low-power commercial applications, using a maximum of 0.5 watt RF power. With a limited number of channels and no use of repeaters, no use of telephone interconnects, fixed/integrated antennas, and a talk timer of 180 seconds, Tier I DMR devices are best suited for personal use, recreation, small retail and other settings that do not require wide area coverage or advanced features.


DMR Tier II covers licensed conventional radio systems, mobiles and hand portables operating in PMR frequency bands from 66-960MHz. The ETSI DMR Tier II standard is targeted at those users who need spectral efficiency, advanced voice features and integrated IP data services in licensed bands for high-power communications. ETSI DMR Tier II specifies two slot TDMA in 12.5 kHz channels.

DMR Tier II is based on the following ETSI standards.


DMR Tier III covers trunking operation in frequency bands 66-960MHz. The Tier III standard specifies two slot TDMA in 12.5kHz channels. Tier III supports voice and short messaging handling similar to MPT 1327 with built-in 128 character status messaging and short messaging with up to 288 bits of data in a variety of formats. It also supports packet data service in a variety of formats, including support for IPv4 and IPv6.

Monitoring DMR


GRE \ Radio Shack \ Whistler
  1. Using modified Whistler firmware. See the Whistler Official Upgrade (WOU) article
  2. Firmware CPU 3.8 & DSP 2.9 or better use.
  3. Directly out-of-the-box Whistler announcement.

See their respective wiki articles for additional details:

  1. Firmware 1.07.06 or better, updates via the USB Mini-B port.
  2. Firmware 1.11.15 or better, for both models via the microSD, or the USB Mini-B port.

Using a computer it’s possible to use DMRDecode to view and decode system and channel data with a receiver – either the Discriminator output of a scanner OR with a variety of Software Defined Radios (SDRs) devices. Using DSD or DSDPlus to further decode data and voice

Information and links provided on this page, is courtesy of

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