Common control

In telecommunication, a common control is an automatic switching arrangement in which the control equipment necessary for the establishment of connections is shared by being associated with a given call only during the period required to accomplish the control function for the given call.

Note: In common control, the channels that are used for signaling, whether frequency bands or time slots, are not used for message traffic.

Source: from Federal Standard 1037C and from MIL-STD-188