z h.f. 45.5.1 Applications 445.9MHz to 445.975MHz u.h.f. Talkback frequencies at 146MHz, 161MHz and 422MHz. On site paging systems are intended for the coverage of a premises or a local site completely within the user's control. These systems are usually owned and licensed by the user and vary from a single 45.3.7.2 Wide area low power transmitter/control unit operating with 5 pagers to large high power, multi-site, multi-access systems with 1000 or more Public system (OPS) 469.5MHz; 469.65MHz and 469.95MHz. pagers. All three types of pager can be used in on site applications but, 45.3.8 Sweden because speech messages are also permitted, tone alert and numeric systems have generally satisfied the needs of staff location and one 45.3.8.1 On site way message transmissions. By preprogramming a series of fixed alpha messages into the 26.1MHz to 26.958MHz. receiver's memory, which are displayed on receipt of predetermined Talkback 160MHz. number sequences dialled by the calling party, a numeric pager provides many on site alpha numeric functions at low cost. With the growing demand for the transmission of data in the health care 45.3.8.2 Wide area market and process industries, the on site alpha pager is becoming more in demand. 169.425MHz to 170.0375MHz Public Regional Paging Service Sites vary from large warehouse areas with few personnel, where (MiniCall). travelling time is saved by updating requirements from stores office On site paging 45/5 to fork lift truck driver, to densely populated sites such as hospitals As the market demanded more features and facilities and even where emergency calls for groups of staff (cardiac arrest teams) can smaller receiver size, digital code formats were devised. Unfortu- be summoned as a unit by the group call facility. A waitress, with a nately the benefits, such as the narrow noise bandwidths of the two tone pager, can be notified by the chef when her next order is ready, tone systems, meant a sensitivity loss, when using digital formats of and a broker can be continuously upd