Channel-associated signaling

Channel -linked signaling or channel - associated signaling (CAS ) refers to signaling processes that are without signaling channels. The signaling information required for a call to be transferred to the voice channel.

CAS signaling methods are relatively old, they have already been introduced at the beginning times of the phone. Today CAS is only used for analog phones. Today, instead methods of common channel signaling (English common channel signaling ) used, which used separate channels for signaling information (D - channel signaling system no. 7).

Is signaled to CAS via signals which may be different from the co-transmitted language, for example DC voltages, low-frequency vibrations below the voice band, frequencies above the voice band, particularly frequency mixtures which do not occur in speech, pulses.

Are hereby transferred as ring signals ( ringing voltage ), outgoing (pulses, audio frequency mixtures), metering pulses. Because of limited ability to generate signals with CAS signaling information are kept very simple so that usually can be controlled so that only connecting and disconnecting.

• Switching technology