A CIRCUIT TO PROVIDE BACKUP TELEPHONE SERVICE FOR A MULTIPLESERVICE ACCESS SYSTEM USING A TWISTED PAIR

摘要

The present invention relates to a safety device for multiple access subscriber link over a wire pair connecting a subscriber server to at least first and second network interfaces. The first network interface has a port that is directly connectable by a conductor to a telephone such that the telephone is operable without power being supplied from the telephone. The device is comprised of a remote modem at th e second network interface connected to the subscriber link. A local modem of the server is provided in communication with the remote modem over the subscriber link. A telephone is provided which uses a first portion of a frequency spectrum of the subscriber link. The local modem and the remote modem use a second portion o f the frequency spectrum. The telephone is connected directly to the remote modem through the wire pair at a remote end. The remote end of the wire is one of connecte d to the port one of directly and selectably through a switch.