It is a device capturing and controling all the signals, which are being created by the whole system, especially the made and received phone call signals. The device is mostly used for connecting regular phone system with the Internet and backwards.
Introduction
With a traditional PBX system, or private branch exchange, everything is done over live phone lines. Stations are utilized to route and reroute phone calls in order to allow a caller to reach the party they want to talk to. While this is a perfectly acceptable method of doing business, as technology grows, so do the incentives for upgrading to newer business telephone systems.