Abstract: A method and system for arranging a common channel signal through an ISDN in a switching network. In the switching network, a signal is transferred between the switching stations in a common channel signalling manner. This method and system serves to allocate a signal path between the stations through the ISDN without having to provide a dedicated channel between the stations as a common channel signal path. Then, the method and system establishes a temporary connection between the stations through the ISDN using a channel in the ISDN (for example, D channel) used for controlling the call setup between the ISDN and a terminal and transfers a common channel signal between the stations by transferring transparent user information to the ISDN. In the common channel signal network in which a common channel signal is transferred through a leased line, the signal transfer is switched from the leased line to the ISDN when failure takes place in the common channel signal path.

Abstract: A switching control system is provided for an electronic switcher employing a common channel signalling. This system is designed to keep the common channel signalling for a speech path in parallel to the associated signalling system, invalidate the speech information in the associated signalling system for a speech path if the signal link is in a normal state and control the speech path in the common channel signalling system, and if failure takes place on the signal link, control the speech path in the associated signalling system.