Control data transmission system for private branch exchange

A control data transmission system for use in a private branch exchange, comprising:

• a control data highway;
• a plurality of line/trunk cards coupled to said control data highway and to each of which are coupled a plurality of terminals of the same type, a plurality of line/trunk cards associated with said terminals of the same type constituting a group, each of said line/trunk cards including an interface section coupled to said data control highway and to which are coupled address information inherently allocated to the respective line/trunk card and group address information commonly allocated to line/trunk cards belonging to the same group, a programmed port controller coupled to said interface section for receiving control data transmitted over said control data highway and addressed to itself, and terminal interface means coupled to said port controller to control said terminals in accordance with the control data;
• control means including data storage means for storing control data and control programs corresponding to the types of terminals, and data transmitting means coupled to said data storage means for sending in a predetermined format onto said control data highway, a control signal containing address information designating an individual line/trunk card or a group of line/trunk cards belonging to the same type and subsequent control data for controlling said terminals;
• said interface section of each of said line/trunk cards including address detecting means for detecting the address information in the control signal transmitted over said control data highway and for, upon detecting the address information allocated to it and a group address of the group to which it belongs, issuing a request to receive the control data subsequent to the address information to said port controller;
• and
• said control means being arranged to transmit the group address information and program data onto said control data highway when loading a program corresponding to the type of the terminals into said port controller in each of said line/trunk cards.