Telephone system operation - in which main phone is controlled by central controller and extensions can be added by 4-line

摘要

Method of operation of a telephone system comprising a main telephone (1) and several connected telephones (2, 3 etc). The main telephone (1) is connected to an externally powered central control unit (RKES) which is coupled to the lines of a telephone network to enable connection to the other telephones via a four line bus. Speech is transmitted over two lines and the other two lines carry control commands and power. A local control unit (RKET) is connected between each telephone and the bus, which communicates with the central control unit (RKES). The speech lines can connect the speech path between a telephone and an exchange or between two telephones. ADVANTAGE - Allows further connection. Also compact and convenient. Telephones may be used in every room, or wherever required.