ISO IEC 21410:2001 pdf download – Information technology — Telecommunications and information exchange between systems — Corporate telecommunication networks — Signalling interworking between QSIG and H.323 — Call transfer supplementary services. 1 Scope This International Standard specifies signalling interworking between “QSIG” and “H.323” in support of the call transfer supplementary services within a Corporate telecommunication Network (CN). “QSIG” is a signalling protocol that operates at the Q reference point between Private Integrated Services eXchanges (PINX) within a Private Integrated Services Network (PISN). The Q reference point is defined in ISO/IEC 11579-1. A PISN provides circuit-switched basic services and supplementary services...