The present document defines the signalling protocol for the purpose of bearer control at the Q-reference point between Private Integrated Services Network Exchanges (PINXs) connected together within a Broadband Private Integrated Services Network (B-PISN) employing Asynchronous Transfer Mode (ATM). The present document is part of the B-QSIG signalling system. The present document specifies the essential features@ procedures@ and messages required for establishing@ maintaining and clearing of bearer connections to point-to-point multiconnection calls at the B-QSIG interface in a functionally separated call and bearer control environment. Bearers are controlled independently by means of a separated call control protocol. The separated call control protocol is assumed to be that specified in ECMA-294 [4]. The present document is applicable to PINXs that support separated call and bearer control protocol at the Q reference point. The Q reference point is defined in ISO/IEC 11579-1 [2].