Abstract: Gateway device (21) for mounting as an interface between a concentrator (9) of a switched circuit network and a call server (7) of a time-switched network, the concentrator (9) being provided for handling calls of a plurality of subscribers of different access networks (14-16), the gateway device comprising a series of gateway units (22a-c), each having a media gateway (24a-c) and a first (22a) having a first signalling gateway (23a), each media gateway (24a-c) comprising a number of resources for connecting calls between the concentrator (9) and the call server (7), the first signalling gateway (23a) comprising: memory means for storing assignment data about the resources of each of the media gateways (24a-c); means (6) for receiving a call initiation signal associated with an incoming call originating from any of the subscribers of any of the access networks (14-16); means for selecting and assigning an available resource of any of the media gateways (24a-c) to the incoming call based on the assignment data