QSIG is an ISDN based signalling protocol for signalling between nodes of a Private Integrated Services Network (PISN). The Qsig protocol will carry user and feature information between switches. It will allow common features such as Camp On and Call Back to be offered across all nodes in the network, Thus for a large or very distributed company that requires multiple nodes, users will receive the same services across the network and need be unaware of the switch that their telephone is connected to. This greatly eases the problems of management of large networks Telephony
