digital access signalling system (DASS)

The Digital Access Signalling System (DASS) is a protocol widely used in England to support ISDN services.

The DASS protocol already exists in its second version as DASS II, and it can be assumed that this protocol will be replaced in the coming years by Q.931, which is increasingly used in Europe.

DASS II is a protocol for signaling in the D- channel of ISDN, which is used for connection setup and termination as well as for connection control.