Key telephone station set circuit

#1. Field of the Invention

#This invention relates to telephone station set circuits and, in particular, to circuits responsive to digital control signals for implementing key telephone functions at the station set.

#2. Description of the Prior Art

#The aforementioned objects and features of the invention, as well as other objects and features, will be better understood upon a consideration of the following detailed description and the appended claims taken in conjunction with the attached drawings of an illustrative embodiment in which:

#FIG. 1 is a simplified block diagram showing the interconnections between the station set and other centrally located apparatus;

#FIG. 2 illustrates the physical design of the station set;

#1. Overview of System Operation

#The simplified block diagram of FIG. 1 illustrates the interconnections among all major components to effect key telephone system operation. Specifically, there is shown a number of key telephone station sets designated 110-1 through 110-n. Each of the station sets 110 is connected to a PBX 112 by a two-wire talking path designated T and R. In particular, station set 110-1 is connected to PBX 112 by leads T1 and R1 and station set 110n is connected via leads Tn and Rn.

#Data is transmitted from station sets 110 via leads 121 to a station interface controller 111. Correspondingly, data from interface controller 111 is transmitted via leads 122 to station sets 110. The exchange of data between interface controller 11 and cross-connection network 113, to establish a path through network 113, is effected through common control network 114. Once a path through network 113 is established, a connection to central office 116 is completed via one of line circuits 115-1 through 115m and one of lines L1 through Lm.