Short Answer
DMR Tier I refers to license-free digital short-range radio, Tier II to conventional professional DMR business radio with direct operation or repeaters, and Tier III to DMR trunking with dynamic channel allocation. For companies, Tier II is usually relevant when robust group communication with dedicated channels, repeaters and clear programming is required. Tier III becomes valuable for larger networks with many groups, locations, and higher capacity.
The DMR tiers help to correctly classify digital radio solutions. They do not replace project planning, but provide clear guidance for device selection, frequencies, and system architecture.
Comparison of DMR Tier I, II and III
| DMR Tier | Classification | Typical Use |
|---|---|---|
| Tier I | License-free DMR in the 446 MHz range. | Simple short-range communication. |
| Tier II | Conventional DMR business radio with direct operation or repeater. | Companies, industry, security, municipalities. |
| Tier III | DMR trunking with dynamic resource management. | Large networks, many groups, multiple locations. |
Which tier fits?
For most professional Motcom projects, DMR Tier II is the entry point: planable frequencies, repeaters, time slots, groups, emergency functions, and accessories. Tier III becomes interesting when capacity, roaming, central control or many user groups become important.
Typical Errors
- Tier I is confused with professional business radio.
- Tier II is purchased without clarifying frequency allocation and channel plan.
- Tier III is considered solely a device issue, although it is a system project.
FAQ
What is DMR Tier II?
DMR Tier II is conventional digital business radio, usually with dedicated frequencies, direct operation or repeaters.
Is DMR Tier I license-free?
Tier I is intended for license-free DMR short-range radio, but only with suitable devices and within the applicable rules.
When is DMR Tier III needed?
When many users, groups, locations or dynamic channel management are required.
Is a Motorola R7 Tier II?
The Motorola MOTOTRBO R7 is typically used in professional DMR systems. The specific use depends on programming and the system.
Sources and Updating
This page was created on 06.07.2026. Technical and regulatory information must be cross-referenced with current manufacturer data, standards, frequency specifications, and site conditions for specific projects.