Cisco Single-Wide High Density Analog Voice Service Module With 16 FXS And 2 FXOThe Cisco Single Wide High Density Analog Voice Service Module is purpose built to deliver scalable, reliable analog voice and fax connectivity directly into Cisco 4000 Series Integrated Services Routers (ISRs). With 16 FXS ports and 2 FXO ports, this high density module enables enterprises, managed services providers, and service providers to bridge traditional telephony equipment and public switched telephone networks (PSTNs) with modern IP based