Digital Subscriber Signalling System Number 1

Digital Subscriber Signalling System no 1 This is an ISDN user network interface. It is a common channel digital access signalling system. ITU-T recommendation is Q.931 and ETSI EN 300 403-1

A set of protocols in ISDN designed so your equipment can ask for specific services across the network. Directed at the carrier's switching equipment, DSS1 sends message types that provide the specific control (for example, connect, hold, and restart) to be taken.