WIRELESS DIGITAL SUBSCRIBER TELEPHONE SYSTEM FOR SIMULTANEOUSLY PERFORMING MULTIPLE AUDIO COMMUNICATION OR DATA COMMUNICATION THROUGH SINGLE OR PLURAL CHANNELS

摘要

PROBLEM TO BE SOLVED: To attain the effective utilization of a frequency, improvement in the stability of operation, cost-down and improvement in performance by enabling the transmission of at least two-way simultaneous calls with prescribed band width. SOLUTION: A private branch exchange(PBX) 15 converts audio information to the digital sample of 64 kbps μ-law compression pulse code modulation(PCM). That digital audio information is processed by an audio compression system. Each channel control unit(CCU) 18 extracts transmission channel output from an encoder/decoder 16 of a correspondent single voice encoder/decoder (VCU) 17 and transmits data to a modem device 19 in the proper time slot and proper format. The properly formatted transmission data from each CCU 18 are transmitted to the modem 19 at the rate of 16K symbols/sec. Respective RF/IF processor (RFU) 21, modem 19, CCU 18, VCU 17 and PBX 15 are originally fully duplexed. Thus, at least two-way simultaneous calls can be transmitted with the prescribed band width.