Signaling

1. The use of signals for controlling communications.

2. In a telecommunications network, the information exchange concerning the establishment and control of a connection and the management of the network, in contrast to user information transfer.

3. The sending of a signal from the transmitting end of a circuit to inform a user at the receiving end that a message is to be sent.

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