Abstract: A system and method for routing calls from a time-division multiplexed (TDM) sets in an IP network to a geographically appropriate portion of the public switched telephone network (PSTN). A call is routed to an edge gateway in a geographic location corresponding to the geographic location of an IP media gateway to which the TDM set is connected. Each IP media gateway is associated with a geographic zone. Each geographic zone is also associated with at least one edge gateway. Accordingly, incoming calls are routed by the central call server based upon the geographic zone associated with the IP media gateway receiving the call, and are routed to an edge gateway associated with the identified geographic zone. The system and method may be applied to route emergency service access calls to an appropriate portion of the PSTN so that they arrive at a geographically appropriate public service answering point (PSAP).

Abstract: A quality of service (QOS) server gathers information in relation to transport introduced delays and obliterations of so called real-time protocol (RTP) signal streams which are used to packetize signals of synchronous signals origins, for example origins such as telephones and raster scan apparatus, for transport via the IP network. The QOS server is able to provide recently gathered QOS information about a requested call, apriori the actual call set up. In an example of a PBX call centre, an automatic dialler is coupled with a QOS server and in relation to endpoint and route selected data, determines if an IP telephony call should proceed, contingent upon the probable QOS being sufficient, before a call controller initiates a call set up.