Centrex or PBX: Wireless Centrex

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Wireless Centrex

A number of value-added services are available through wireless Centrex. Pacific Bell's Wireless Centrex, for example, combines a existing Centrex Service with Ericsson's Freeset Business Wireless Telephone system to create a private, wireless environment at a company's business location without incurring expensive cellular airtime charges. At the corporate facility multiple, overlapping cells cover assigned areas. The number of cells required is determined by traffic density at a given location.

An on-premises system called the Radio Exchange handles such functions as powering, control, and facilities for connection to Centrex. Base Stations relay calls from the Radio Exchange to the Portable Telephones. Each Base Station provides multiple simultaneous speech channels. The coverage of each Base Station depends on the character of the environment, but it is typically between 8000 and 15,000 square feet. Portable Telephones contain the intelligence needed to accommodate roaming and cell-to-cell handover.

When the Radio Exchange receives an incoming call, it transmits the identification signal of a Portable Telephone to all Base Stations. Because the Portable Telephone communicates with the nearest Base Station, even in standby mode, it receives the signal and starts ringing. When the call is answered, the Portable Telephone selects the channel with the best quality transmission.

Pacific Bell's Wireless Centrex service gives business users full wireless mobility, plus the following options: