An Overview of DMR Tier II Repeaters, IP Connect, XPT, and DMR Tier III Trunking Systems
The DMR Standard
Digital Mobile Radio (DMR) is the open radio industry standard that uses TDMA technology to divide a single 12.5kHz channel into two time slots, allowing two separate conversations to take place at the same time. DMR offers numerous advantages over analog radio systems, including improved voice quality, longer battery life, double the call capacity, and support a wide variety of flexible calling options.
DMR standards compliance in radio systems ensures that all radios and repeater sites operate to a common standard and enables the creation of a robust and reliable communication system. The benefits of DMR standard compliance include guaranteed manufacturer interoperability, reliable performance, and future-proof systems that remain compatible and functional for years to come.
Learn more about the DMR standard
Radio-to-Radio Systems
For smaller groups of radio users, radio-to-radio deployments provide a simple and cost-effective solution that provides an easy upgrade path from analog to digital DMR radios. Program the call groups and the system is up and running with no need for any radio system infrastructure. The limitations of DMR radio-to-radio deployments are call capacity and coverage area.
DMR Tier II Systems
DMR Tier II repeater sites use DMR standard compliant radios and require FCC licenses. Tier II repeater sites are deployed to increase the coverage area, improve the signal quality, and increase the group calling capacity.
A DMR Tier II Repeater Site consists of a DMR repeater, antenna systems, and supporting equipment. Repeaters receive low‐level signals from handheld and mobile DMR radios and retransmit the information at a higher power level over a greater area. Repeaters provide an intelligent and seamless communication platform with the flexibility to connect with a variety of systems.
A dispatch application (also called a dispatch console) is a client software application that provides centralized control and monitoring of the DMR Tier II radio system, including voice calls, GPS location tracking, messaging functions, and voice recording. It enables the dispatcher to communicate with multiple radio terminals simultaneously and monitor the activity on the system.
DMR Tier II systems provide many benefits, but the coverage is limited to a single repeater site (base station) location.
Learn more about DMR Tier II Conventional Repeater Systems
IP Connect Systems
IP Connect uses an IP Network to connect several DMR Tier II repeater sites for a larger radio network. IP Connect offers greater coverage, simple migration, ease of use, and supports instant, real time radio communications between distant radio sites. IP Connect can be deployed with a simple license upgrade to a DMD Tier II repeater and IP network connectivity. IP connect expands the coverage area, but not the calling capacity of Tier II repeater sites.
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XPT Systems
Extended Pseudo Trunk (XPT) is an exclusive Hytera radio technology that enables trunking of radio channels to increase the group calling capacity of Tier II repeater sites with the addition of a network switch to manage the talk channels on multiple repeaters. XPT can be deployed at a single repeater site, or the trunked channels can be transported over an IP network to connect multiple XPT sites over a wide area. XPT can be deployed with the addition of a layer 2 switch and an XPT repeater license. While XPT dramatically increases the group calling capacity with a minimal investment in network equipment, it is not designed for organizations that have a high capacity of individual radio-to-radio calls and require comprehensive access control for the radios.
Learn more about Hytera XPT Pseudo Trunking
DMR Tier III Systems
DMR Tier III Trunking is the premier radio systems technology and is designed for the most complex communications operations in large organizations. DMR Tier III is an IP-based digital trunking system designed to provide high-capacity individual and group calling, dispatching, and radio management capabilities across wide geographic areas.
Tier III trunked radio systems optimize voice or data traffic through a limited number of frequencies, maximizing the available resources for a large group of users, and utilizes repeater technology with a dedicated control channel, managed by servers. The DMR Tier III Trunking System consists of a central controller called a Mobile Switching Office (MSO), a Base Station Controller Unit (BSCU) server at each radio repeater site, multiple repeaters to carry the traffic, and a wide area network that connects all the different pieces together. Tier III systems consist of the application layer, the network layer, and the radio terminal layer.
SMR networks are wide area commercial radio networks that leverage DMR Tier III technology to deliver secure communications services to thousands of users with mission critical reliability.
Learn more about DMR Tier III Trunking Systems
Systems Overview Comparison Table
| System Type | Coverage | Call Capacity | Software and Features |
| Radio-to-Radio | Limited to the TX power of the radios | Two Slot TDMA, single channel with simplex calls | Group and individual calling, worker safety features, Bluetooth, and texting |
| DMR Tier II | Expanded coverage to larger sites using repeaters and antenna | Two Slot TDMA, single channel with full duplex calls | Dispatching, recording, and monitoring software, GPS location tracking, flexible system interconnects, advanced encryption |
| IP Connect | Connects multiple Tier II repeater sites via IP networks | Two Slot TDMA, single channel with full duplex calls | All radio and DMR Tier II features, plus group calling across multiple remote sites |
| XPT | Same as a single XPT (Tier II) repeater site, and can connect multiple sites via IP networks | Pseudo trunking expands group calling capacity with up to 16 channels | All radio and DMR Tier II features, plus trunked channels to multiple remote sites |
| DMR Tier III |
Wide area based on number of repeater sites and available frequencies | DMR Tier III trunking enables unlimited individual and group calls based on frequency availability and number of repeaters | All radio and DMR Tier II features, plus redundancy and resiliency, advanced security and access control, user management, and call prioritization |
