OPTICAL EXTENSION DEVICE FOR SUBSCRIBER'S LINE

摘要

PURPOSE: To extend a telephone line interconnecting telephone sets without use of a cable. CONSTITUTION: A line multiplexer 1 contains plural station side telephone lines 50 such as trunk lines and extensions of an exchange 5 and multiplexes signals received by each of the station side telephone lines 50 and information representing the control state by the station and exchange 5 and sends them by an infrared laser beam transmitter 2a. On the other hand, a terminal equipment multiplexer 3 accommodates plural telephone sets 4 and demultiplexes the multiplexed signals received by an infrared laser beam transmitter 2b and distributes the signal to each telephone set. Furthermore, the state of the telephone lines 40 accommodating each telephone set is controlled to be the same as the state of the station side telephone line. The terminal equipment multiplexer 3 and the line multiplexer 1 relays the signal from the telephone set to the station side telephone line to control the state of the station side telephone line 50 so that it reaches the same state as that of the telephone line 40 controlled by each telephone set.