The "Digital Mobile Radio" standard adopted by ETSI is a two-way radio standard based on a two-slot 12.5 KHz TDMA technology. This technology is also used in GSM cellular and TETRA professional networks however with various channel bandwidth.

The DMR protocol provides advanced voice and IP services specifications in licensed bands within the VHF and UHF frequency ranges. High power communications are used in mobile and portable equipment which gives a great flexibility to professional organizations, government and public safety services to adapt their equipment to the new standard with a quite small investment. Furthermore the spectral efficiency beeing increased to avoid traffic congestion and channel interference.

Professional users operating in the analog PMR bands would take advantages to migrate to the DMR equipment by increasing the system capacity, improving the voice quality and coverage areas while holding their license. Organization's equipment may evolve to support both conventional and trunked radio system.

The low loss duplexer filter SPD15057R provided by MCR TELECOMMUNICATION is used in DMR 2-way radio station or repeater to connect the transceiver T/R ports to a single antenna. The duplexer handles up to 200 W 50% dc average power and thus can be suited to increase the system capacity by combining up to 4 transceivers of 50 W output power each. It operates in the VHF ranges 136-179 MHz and may be easily tuned within a bandwidth of 10 MHz.

This duplexer filter is that used in the multiplexed 4-channel base station MDBS91504CD.