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===PMR===In the United Kingdom they have PMR / Private Mobile Radio or Professional Mobile Radio which is similar to LMRS in the United States. Like LMRS these are field radio communications systems which use portable, mobile, base station, and dispatch console radios.In general narrow band frequency modulation is the chosen form of modulation, although airport services use amplitude modulation. Typically a deviation of 2.5 kHz is used for FM and this enables a channel spacing of 12.5 kHz to be implemented. As the demands for PMR are high, it is necessary to make effective use of the channels available. This is achieved by re-using the frequencies in different areas. Base stations must be located sufficiently far apart so that interference is not experienced, and also selective calling techniques such as CTCSS and DTMF are used to ensure that as many mobiles as possible can use a given channel.*TETRA is a modern standard for digital private mobile radio (PMR) and public access mobile radio (PAMR).*MPT1327 is a popular PMR trunking system