Abstract: In this invention, a call control information of a subscriber's line is compiled into a packet form, is transferred via a network of a digital switch board to a signal control device, and digital data is also transferred via the network to a handler. Accordingly, a signal from a digital subscriber is efficiently processed, and an analog subscriber is also accommodated so that a call control in the same way as for the digital subscriber is made possible for the analog subscriber.

Abstract: A digital switch module for a time division digital switching system includes an encoding law conversion memory and a control memory. The encoding law conversion memory has previously stored therein conversion data for converting between different types of encoding laws. For example, the A-law and .mu.-law encoding laws set forth in CCITT Recommendation G.711 can be converted by a digital switch module according to the present invention. The encoding law conversion memory includes a read only memory having regions for conversion between A-law and .mu.-law encoded data and for nonconversion of both A-law and .mu.-law encoded data. The control memory designates which of the regions in the encoding law conversion memory is to be used during each time slot, thus dynamically controlling whether data passing through the digital switch module is converted or not. The type of conversion or nonconversion designated by the control memory can be determined by the type of data, e.g.