Common Channel Signaling (CCS) is the transmission of signaling information out of the information band. In communications, transmission is the act of transmitting electrical messages (and the associated phenonomena of radiant energy that pass through media). ... Signaling, or signal, may mean: Look up signal on Wiktionary, the free dictionary. ... Information is a word which has many different meanings in everyday usage and in specialized contexts, but as a rule, the concept is closely related to others such as data, instruction, knowledge, meaning, communication, representation, and mental stimulus. ...

In CCS, one channel of a communications link is be used for the sole purpose of carrying signaling for establishment and tear down of calls. The remaining channels are used entirely for the transmission of voice or data. In most cases a single 64kbit/s channel is sufficient to handle the call setup and teardown traffic for numerous voice and data channels.

Compare with Channel Associated Signaling, generally implemented using robbed-bit signaling, where the signalling information for each channel is transmitted within the channel itself and as a result, reduces the amount of bandwidth available within the channel (in some cases by as much as 12.5%). Channel Associated Signaling CAS signaling is a form of digital communication signaling. ...

The most common CCS signalling methods in use today are ISDN and SS7. An ISDN Telephone Integrated Services Digital Network (ISDN) is a type of circuit switched telephone network system, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds than available with analog systems. ... Signalling System #7 is a set of protocols defined by ITU-T, specifically in the Q.7* set of documents, used to set up telephone calls. ...

ISDN signalling is used primarily on trunks connecting end-user PBX systems to a central office. SS7 is primarily used within the PSTN. The two signalling methods are very similar since they share a common heritage and in some cases, the same signalling messages are transmitted in both ISDN and SS7. PBX redirects here. ... The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ...