CAS

Revision as of 10:54, 7 August 2009

Channel Associated Signaling is a signaling protocol for the set-up and tear-down of phone calls. It is different from other signaling protocols such as SS7 in that it is not message/packet-based but rather based on bit transition for state changing, and tone transmission for information and state information exchange. In many parts of the world, CAS was first replaced by ISDN and in many cases, was ultimately replaced by SS7. Today, CAS is often used with low density trunks.

CAS and TelcoBridges

As of July 2009, CAS signaling is supported at the basic API level but is not supported at the Toolpack / Web Portal level and is thus not accessible for more basic applications (i.e., that don`t require programming code). TelcoBridges is investigating the possibility of exposing access to CAS at the web portal level or higher. We are also looking at options that will enable the solution developer or the service provider to the CAS stack according to local variants, without having to request a new stack variant from TelcoBridges.

Supported variants

The following CAS variants are currently supported at the basic API level:

RBS T1 variants:

• Wink start
• FXS Ground start
• FXS Loop start
• FXO
• Taiwan R1

R2 CAS variants:

• China
• Korea
• Singapore
• Bangladesh
• Generic (ITU spec base)

Please contact TelcoBridges regarding support for additional variants.

References

Wikipedia article