circuit indentification code (SS7) (CIC)

The Circuit Identification Code (CIC) is used to assign the signaling message to a user channel of ISDN or GSM.

The CIC code is a 12-bit long data field Signalling Link Selection( SLS) of the Message Transfer Part( MTP) in the SS7 protocol which is used to determine the switching line.

The Circuit Identification Code is subject to a number of conventions, including that the designations are adapted to the network operator, that only user channels with different CIC codes may be operated between two network nodes, and that the two network nodes connecting a user channel have the same Circuit Identification Code. The Circuit Identification Code is described in ITU-T Recommendations Q.762 and Q.763.