Extended Loops for Distant Phones and Fax Machines

Higher Ringing Voltage and Loop Current
By Cisco Systems

Published 2008; Posted January 2009

Abstract:

Enterprises are turning to voice-over-IP (VoIP) and IP telephony solutions for voice communications in corporate and branches so that they can reap the benefits of converged networks and feature-rich IP-based telephone systems. While enterprises are making the migration to IP telephony, on many occasions legacy analog phones, modems, and fax machines continue to be important and vital components in the network.

Applications exist that require extended loops between the analog phones and the gateway. Examples include phones in multi-story buildings, on large campuses, in large railroad yards, in large industrial plants, and in remote locations such as utilities applications. Other applications require accommodations for specialty phones, including elevator phones, emergency kiosk phones, and neon-lamp phones.

Cisco^® has added the Enhanced Foreign Exchange Station / Direct Inward Dialing (FXS/DID) Voice Interface Card (VIC3-2FXS-E/DID) to its FXS portfolio to address the need for longer loop lengths and to accommodate specialty phones. The VIC3-2FXS-E/DID offers higher ringing voltage for longer loops and increased FXS feed current for specialty phones. It is thus able to accommodate remotely located phones, fax machines, or modems up to 11,000 feet (3.4 kilometers). It is able to drive many specialty phones requiring higher loop power for proper operation.