Key telephone system for subscribers

Abstract

A key telephone system for subscribers is disclosed which includes at least a plurality of key telephone stations, a subscriber common equipment which connects the key telephone stations to each other and further connects the key telephone stations and an private automatic branch exchange, wherein said subscriber common equipment comprises switching network circuits, a register connecting circuit, line circuits, intra-office circuits, line circuit links, intra-office circuit links and a common controller, whereby each of said key telephone stations is connected to the subscriber common equipment through a pair of speech lines and a few control lines, and further said key telephone station can handle data processing services through said control lines by using a data terminal equipment attached to the key telephone station and a data processing unit by way of said subscriber common equipment.

What is claimed is: 
     
       1. A key telephone system for subscribers comprising: a .Iadd.plurality of .Iaddend.key telephone .[.station.]. .Iadd.stations .Iaddend.(ST) .Iadd.each .Iaddend.having indication lamps (for example, LP, PLP, OPBL) which indicate the status of .[.the.]. .Iadd.each .Iaddend.key telephone station, and a plurality of function buttons (for example, OPB, PB, HLD, INTR, INTO): a subscriber common equipment (CE) which is comprised of a plurality of connecting network circuits (for example, CNW 0 , CNW 1  . . . CNWn), line circuits (LC), intra-office circuits (IC) and a common controller (CC) which controls said connecting network .[.cicuits,.]. .Iadd.circuits, .Iaddend.line circuits and intra-office circuits, where said connecting network circuits connect a speech line (SL) of one key telephone station and a speech line (SL) of the other key telephone station by using a register connecting circuit (RGC) and switching network circuits (for example, SNC 0 , SNC 1  . . . SNCn), each of which switching network circuits cooperates with both line circuit links (for example, LCL 0 , LCL 1  . . . LCLn) and intra-office circuit links (for example, ICL 0 , ICL 1  . . . ICLn); and control lines (CL) which connect each of said key telephone stations and said subscriber common equipment, wherein a desired one of said line circuit links is caught .[.by dialing a desired line circuit number by push button means (PB) of said common controller.].  .Iadd.by means of said common controller when dialing a desired line circuit number by using push buttons (PB), .Iaddend.which desired line circuit number is indicated on said indication lamp (LP), while the desired one of said intra-office circuit links is caught by pushing a desired intra-office button (for example, INTR. INTRO), by means of said common controller. 
     
     
       2. A key telephone system for subscribers as set forth in claim 1, further including: .[.a.]. data terminal .[.equipment.]. .Iadd.equipments .Iaddend.(TAM) located on said key telephone station side; a .[.first.]. data separator (CAN) and a .[.second.]. data separator (COR) .[.which are inserted in.].for connecting both said key telephone station (ST) and said data terminal equipment (TAM) with each other by way data control lines (CL') .[.between said key telephone station.]. .Iadd.; .Iaddend.and .Iadd.a data separator (CIR) for connecting both .Iaddend.said common controller (CC) .[.; a third data separator (CIR) which is inserted in.]. .Iadd.and a central data processing unit (CPU) with each other by way of .Iaddend.data control lines (CL") .[.between said common controller and a central data processing unit (CPU).].; wherein data relating to said key telephone station are transmitted through said control lines (CL) during a first time-slot by way of said .[.first, second and third data isolators.]. .Iadd.data separators (CAN), (COR) and (CIR), .Iaddend.and data relating to said data terminal equipment are transmitted through both said control lines (CL) and said data control lines (CL', CL") during a second time-slot by means of said .[.first, second and third data isolators.]. .Iadd.data separators (CAN), (COR) and (CIR), .Iaddend.and data relating to said data terminal equipment are transmitted through both said control lines (CL) and said data control lines (CL', CL") during a second time-slot by means of said .[.first, second and third data isolators.]. .Iadd.data separators (CAN), (COR) and (CIR), .Iaddend.whereby data transmission is effected between one of said data terminal equipments and .[.the other.]. .Iadd.another .Iaddend.of said data terminal equipments and between one of said data terminal equipments and said central data processing unit during said second time-slot.