DMR(Digital Mobile Radio) is a digital radio standard specified for professional mobile radio (PMR) users developed by the ETSI(European Telecommunications Standards Institute) and first ratified in 2005. DMR operates within the existing 12.5 kHz channel spacing used in the globally licensed land travel frequency band and meets future regulatory requirements for 6.25 kHz channels. The DMR protocol actually includes modes of operation for commercial applications that are currently focused on Tier II and III licensing categories, but are not authorized (Tier I), licensed commercial (Tier II) and licensed trunk (Tier III).
Digital Mobile Radio is an open digital radio standard for professional mobile radio users developed by the ETSI(European Telecommunications Standards Institute). The advantage of DMR is that it is based on published standards for normal and trunk-type wireless operation. Within these standards, a dispatch interface standard called the AIS (Application Interface Specification) is defined.