Professional mobile radio (also known as private mobile radio (PMR) and land mobile radio (LMR) are field radio communications systems which use portable, mobile, base station, and dispatch console radios. Operation of PMR radio equipment is based on such standard as TETRA and DMR which are designed for dedicated use by specific organizations, intended for general commercial use. Typical examples are the radio systems used by police forces, fire brigades, huge mining companies, power utilities, nationwide and local early warning systems, subway operators, taxi firms, etc. Key features of professional mobile radio systems can include:


> Point to multi-point communications (as opposed to cell phones which are point to point communications)

> Push-to-talk, release to listen — a single button press opens communication on a radio frequency channel

> Large coverage areas

> Closed user groups

> Use of VHF or UHF frequency bands