 two notable system band. Additionally, the ERMES system occupies the band exceptions, however, the communication is only one way and with- 169.425MHz to 169.80MHz. 'Overlay' and emergency systems are out acknowledgement. Each pager has its own address and when the possible in conjunction with mobile radio systems, which cover the paging caller sends a coded transmission it alerts the bearer by band 138MHz to 174MHz. means of an audible tone, a light and/or a vibration. Paging systems fall into two classes called wide area and on site. U.H.F. The wide area user rents a paging receiver on a public service provider's network, while the on site user purchases his own private Private wide area schemes are concentrated in the band transmission system and paging receivers. 454.0125MHz to 454.825MHz. The 'Europage' (pan-European) scheme has been assigned to 466.075MHz. Again it is possible to have overlay systems in the mobile bands 450MHz to 470MHz. 45.2 Markets In Europe the industry has developed from single on site systems, 45.3.2 Germany the first of these being an inductive loop system installed in St. Thomas's hospital by Multitone Electronics in 1956. Transmissions 45.3.2.1 On site were in the range 30kHz to 50kHz and each receiver was tuned to its own unique individual frequency. Loop current of 100mA around 27.51MHz; 40.76MHz and 40.68MHz. 20kHz channel spacing. 200m to 500m length horizontal loops were driven by 5W to 10W 40.665MHz to 40.695MHz. 10kHz channel spacing. drivers. Paging sensitivities of 100uA ft. sq. turn were typical. For 468.35MHz; 468.375MHz; 468.4MHz to 469.150MHz. a narrow tall building a vertical loop was used successfully. Many Talkback 151.07MHz; 160.49MHz to 160.55MHz; 170.55MHZ to such systems are still in use, but the cost of installing the loop cable 170.79MHz. tends to be prohibitive. National wide area systems in Europe, started by the Netherlands PTT in 1964, were followed by public member operator licences 45.3.2.2 Wide area being granted to private consortia. In North America, h