ISO IEC 14843:2003 pdf download – Information technology — Telecommunications and information exchange between systems — Private Integrated Services Network — Inter-exchange signalling protocol — Call Offer supplementary service. 1 Scope This International Standard specifies the signalling protocol for the support of the Call Offer supplementary service (SS-CO) at the Q reference point between Private Integrated services Network eXchanges (PINXs) connected together within a Private Integrated Services Network (PISN). SS-CO is a supplementary service which, on request from the calling user (or on that user’s behalf), enables a call to be offered to a busy called user and to wait...