| 摘要 |
The wireless system includes one or more payphones from which users may initiate payphone calls. A mobile switching center connects telephone calls initiated from wireless payphones to external telephone systems such as the public switch telephone network (PSTN). To meter charges incurred during the telephone call within an external system, the external system transmits periodic metering pulses to the mobile switching center. Each pulse is representative of a predetermined amount of money associated with the telephone call. The rate at which the periodic pulses are transmitted to the mobile switching center depends upon the current billing rate and may be affected by, for example, the time of day. Rather than the forwarding all of the metering pulses to the wireless payphone, therefore consuming a portion of the bandwidth available for wireless telephone calls, the mobile switching center calculates a steady state billing rate from the metering pulses, then transmits only the steady state billing rate to the wireless payphone. The ireless payphone calculates charges associated with the telephone call based upon the steady state billing rate and displays the resulting charges to the user. Once the mobile switching center has transmitted the steady state billing rate signal to the wireless payphone, a second steady state billing signal is not transmitted unless and until the billing rate for the telephone call changes as detected from a change in the rate of received metering pulses from the external system. In one arrangement, the mobile switching center filters out all metering pulses and transmits only steady state billing rate signals to the wireless payphone. In another arrangement, the mobile switching center transmits metering pulse signals to the wireless payphone until the steady state rate has been determined, then transmits a single steady state billing rate signal. If the billing rate changes, the mobile switching center again forwards metering pulses to the wireless payphone until the new steady state billing rate can be determined. |
