Method and system for providing DC power on local telephone lines

Apparatus for supplying to a telephone service an indication of an off-hook condition of a telephone set that is connected to the telephone service by a network that includes a medium that does not allow DC off-hook signaling from the telephone set directly to the telephone service, said apparatus comprising:

• off-hook detector means couplable to the telephone set for detecting an off-hook condition of the telephone set;
• off-hook transmitter means coupled to said off-hook detector means and to the medium for supplying an AC off-hook indication signal to the medium in response to detection of an off-hook condition by said off-hook detector means;
• off-hook receiver means couplable to the medium for receiving the AC off-hook indication signal supplied by said off-hook transmitter means;
• and
• off-hook simulator means coupled to said off-hook receiver means for supplying a simulated off-hook indication to the telephone service in response to receipt of the off-hook indication by said off-hook receiver means.

A method for carrying DC power over a wire pair of a network for coupling a telephone set to a telephone service, the network having a connection point for connecting the network to the telephone service, said method comprising:

• DC coupling a power supply coupler at a point of the wire pair for coupling DC power into the wire pair;
• connecting an AC Pass and DC Stop device in series between the wire pair and the connection point, such that the AC Pass and DC Stop device is connected between the point at which the power supply coupler is DC coupled to the wire pair and the connection point, for substantially conducting only AC telephony signals and blocking DC flow from the telephone service into the wire pair;
• DC coupling a load coupler to the wire pair for coupling DC power to a load from said wire pair independently of the hook state of the telephone set;
• and
• coupling a telephone coupler to the wire pair for coupling the telephone set to the wire pair for passing only analog telephony signals between the wire pair and the telephone set supplying an off-hook signal to the telephone service when the telephone set is off-hook via an off-hook signaling circuit that bypasses the AC Pass and DC Stop device.

A network for coupling a telephone set to a telephone service, the service providing an analog telephone signal having an AC component and a first DC component, said network comprising:

• a wire pair connected for carrying DC power and the AC component of the analog telephone signal;
• a connection point connected between the network and the telephone service for passing the telephone signal to the network;
• a power supply coupler DC coupled at a point of said wire pair to said wire pair for coupling DC power into said wire pair;
• an AC Pass and DC Stop device connected in series between said wire pair and said connection point for passing only the AC component and blocking the first DC component, said AC Pass and DC Stop device being connected between the point at which said power supply coupler is DC coupled to said wire pair and said connection point;
• a load coupler DC coupled to said wire pair for coupling DC power from said wire pair to a load;
• and
• a telephone coupler for coupling the telephone set to said wire pair for passing only the AC component between said wire pair and the telephone set and for supplying DC power from said wire pair to the telephone set while limiting the DC power supplied to the telephone set to a level suitable for proper telephone operation an off-hook signaling circuit connected to bypass said AC Pass and DC Stop device for supplying an off-hook signal to the telephone service when the telephone set is off-hook.