The Digital T1/E1 Packet Voice Trunk Network Module provides a flexible and scalable T1/E1 voice solution for Cisco 2600 and 3600 series multiservice modular access routers and supports up to 60 voice channels in a single network module. A single Packet Voice Trunk Network Module supports both on-premise and off-premise connections to both Private branch exchanges (PBXs) and public switched telephone networks (PSTNs). This product is for enterprise branches and large businesses wishing to migrate to packet-based multiservice infrastructures. It leverages investments in existing legacy telephony equipment and enables the deployment of new packet voice applications while reducing recurring telephony charges.