Method and system for providing DC power on local telephone lines

摘要

A telephone unit device connectable in series between a telephone set and a wire pair coupled to a telephone service and carrying DC power and an AC telephone signal. The device includes: a first connector connectable to the wire pair; a second connector connectable to the telephone set; means connected between the first and second connectors for passing substantially without change the AC telephone signal between the wire pair and the telephone set; and means connected between the first and second connectors for receiving DC power only from the wire pair and converting the DC power to a level suitable for proper telephone operation of the telephone set connected thereto.

主权项

1. A telephone unit device connectable in series between an analog telephone set and a wire pair coupled to a telephone service and carrying DC power and an analog telephone signal, said device comprising: a first connector connectable to the wire pair; a second connector connectable to the telephone set; a signal passing circuit connected between said first and second connectors for passing substantially without change the analog telephone signal between the wire pair and the analog telephone set; and a DC/DC converter connected in series between said first and second connectors for receiving DC power only from the wire pair and converting the DC power to a level suitable for proper telephone operation of the analog telephone set connected thereto
wherein:
said signal passing circuit comprises a transformer composed of a primary winding and a secondary winding and first and second capacitors, each said capacitor being connected in series with a respective one of said windings; andsaid DC/DC converter is connected between said first and second capacitors.