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What are the Three DMR Tiers?

What is DMR and the Different DMR Tiers

An Overview of the Three DMR Tiers and How they are Used

The industry standard Digital Mobile Radio (DMR) consists of DMR Tier I, Tier II and Tier III.  It is important to understand the differences between the DMR Tiers to know which is the best radio system for your specific needs.

DMR Tier I, Tier II, and Tier III Technology

Digital Mobile Radio (DMR) is an open digital mobile radio standard defined by ETSI (The European Telecommunications Standards Institute), and has emerged as a powerful standard for professional and personal communication. DMR offers enhanced audio quality, increased spectrum efficiency, and advanced features compared to traditional analog systems. To cater to various needs and requirements, DMR has been classified into three distinct tiers: DMR Tier I (unlicensed), DMR Tier II, and DMR Tier III. 

Learn more about the features and benefits of the DMR Standard

For a deep dive into DMR technology, download the DMR Association white paper

DMR Tier 1 (Unlicensed)

DMR Tier I, often referred to as “unlicensed DMR,” is commonly used for license-free, low-power, short-range communications. Designed for personal and recreational use, this tier is ideal for small-scale applications such as individual hobbyists, outdoor activities, and community events. It offers a maximum power output of 0.5 watts and supports non-repeater-based communication. Tier I DMR radios work in Direct Mode (radio-to-radio) on public frequencies. Tier I radios are typically simple and cost-effective, offering basic voice services without advanced features like encryption or data transmission. Nonetheless, they provide clear audio and digital clarity, surpassing analog systems in terms of audio quality.

DMR Tier 2 (Licensed Conventional)

DMR Tier II increases capabilities and is designed for professional and commercial use. It operates in licensed spectrum allocations and allows for higher transmit power levels, offering increased coverage and extended range compared to Tier I. Tier II radios employ a Time-Division Multiple Access (TDMA) protocol, dividing each frequency into two time slots, thus doubling the capacity of the channel. This tier provides advanced features such as text messaging, group calling, and enhanced encryption, ensuring secure and efficient communication.

Tier II radios can be deployed in radio-to-radio applications and can also be deployed with DMR Tier II conventional repeater systems. One of the primary benefits of using a DMR Tier II radio system with a repeater is extended coverage. With a simple radio-to-radio application, the range is limited by the power of the radios and the terrain. In contrast, a repeater can transmit signals over a much larger area, including buildings, hills, and other obstacles. This increased coverage allows users to communicate with each other even when they are far apart, which can be crucial in emergency or critical situations.

Using IP Connect, multiple DMR Tier II repeater sites can be connected with a third-party IP or Ethernet network for wide area coverage that enables users to communicate with users at different remote locations anywhere across the country.

DMR Tier 3 (Licensed Trunked)

DMR Tier III is the pinnacle of the DMR hierarchy, designed to cater to large-scale operations and demanding professional environments. Tier III uses trunking technology, which dynamically allocates channels and resources to users on an as-needed basis. This dynamic channel allocation maximizes spectrum efficiency and provides extensive coverage, making it ideal for wide-area communication networks. Tier III supports multi-site systems with seamless roaming capabilities, enabling users to move across different network sites without interruptions. It offers features such as individual and group calls, data services, integrated voice and data, and comprehensive dispatching functionalities. Tier III finds applications in sectors requiring wide-ranging communication networks, including wide-area education communication systems, transportation systems, utilities, and large industrial complexes.

Hytera’s DMR Tier III trunking solutions represent a true upgrade path for Tier II and analog radio system users, and is the only truly DMR Tier III standard compliant system.

Summary

While all three tiers of DMR provide the advantages of digital communication, they cater to different user requirements and operational scales. DMR Tier I is suitable for personal use and small-scale applications, offering cost-effective, license-free communication with basic features. DMR Tier II, operating in licensed spectrum, serves professional and commercial needs with enhanced coverage, advanced features, and increased capacity. Finally, DMR Tier III serves as the pinnacle of DMR technology, providing wide-area coverage, trunking capabilities, and extensive features for large-scale operations.

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