The Cisco VG Series Analog Voice Gateways are Cisco IOS software-based. The Cisco VG310 is a 24-port gateway. The gateway connects analog phones, fax machines, modems, and speakerphones to an enterprise IP voice system, so you can use them as extensions to your Cisco or third-party IP call-control system. Having these devices tightly integrated with the IP-based phone system is advantageous for increased manageability, scalability, and cost-effectiveness. The Cisco VG Series supports high to low concentrations of analog voice ports for modem calls, fax calls, and analog supplementary services.