The practice of exchanging call-control information over a dedicated signaling network separate from the circuits that carry the actual voice or payload data. This architecture prevents users from interfering with network routing commands and allows for faster call setup. Common Channel Signaling System 7 is the classic example of this design.
Heard on the job
Moving to out-of-band signaling stopped the phreakers from using blue boxes to seize trunk lines.
Also heard as
- common channel signaling
Do not mix it up with
- Out-of-band: Out-of-band is the general concept of using a separate channel, while out-of-band signaling specifically refers to call setup and routing in telephony.
Related terms
Out-of-band
Communications or signaling that occurs outside the primary data channel or frequency band.
In-band signaling
The transmission of network control signals over the same channel used for the actual voice or data payload.
Blue box
A historic electronic toll-fraud device used to manipulate long-distance telephone switches.