Digital mobile radio (DMR) is an open digital mobile radio standard defined in the European Telecommunications Standards Institute (ETSI) Standard. It is used in commercial products around the world. DMR uses a two-slot TDMA in a 12.5 kHz channel. This allows two totally independent QSO's on a single repeater frequency pair at the same time. The standard has become popular due to the relatively lower cost compared to other amateur digital modes like D-Star and System Fusion.
Here is a link to some useful information about DMR