Importance

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Abstract

This is a telephone communications system having at least one fixed terminal connected by at least one subscriber's line to a telephone exchange and a plurality of portable handsets, the fixed terminal and the portable handsets having infrared transmitters and receivers for exchanging unit charging information and sound data information, the fixed terminal transmitting to a given handset unit charging signals received from the telephone exchange during a call, each portable handset accommodating a support for a programmable read-only memory and logic circuit for deducting from the programmable read-only memory unit charges corresponding to the unit charging signals transmitted by the terminal, each portable handset further transmitting a pay signal to the fixed terminal after having deducted the unit charge fee from the programmable read-only memory, and the fixed terminal further arranged for cutting off the call in case of failure to receive a pay signal after having transmitted a unit charging signal, interference between portable units being avoided by the use of time multiplexed bursts of pulses.

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First Claim