Power transmission arrangement for telecommunications systems

A power supply arrangement for supplying electrical power from a central office to a remote customer interface comprising electronic circuits and connected to the central office by means of a two wire transmission line for the transmission of digital pulses between the central office and the customer interface unit, said transmission line terminating in one transformer at the customer interface unit and in another transformer at the central office;

• the arrangement comprising two power sources in the central office each having a ground terminal connected to earth ground, one power source being connected to each wire of the two wire transmission line, and a pair of capacitors connected in series between the two wires of the transmission line and the transformer at the central office;
• the transformer at the interface unit comprising a center tapped coil having end points connected to the wires of the transmission line;
• the interface unit comprising a power converter circuit having a ground terminal connected to earth ground and an input terminal connected to the center tap, for providing power to the interface circuits.

An arrangement for supplying electrical power from a central office to a remote customer interface unit connected to the central office by a pair of transmission wires terminating in a transformer at the central office and at the interface unit for the transmission of digital pulses between the central office and the remote interface unit, the power supplying arrangement comprising a pair of power sources at the central office, each power source having an output terminal connected to one of said transmission wires and a ground terminal connected to earth ground for separately supplying power to each wire of said pair of wires, the interface unit having at least one electrical circuit having an input terminal and having a ground terminal connected to earth ground, said transformer terminating said transmission wires at the interface unit comprising a center tapped coil having end terminals connected to said pair of wires and a center terminal connected to said input terminal of said at least one electrical circuit, whereby electrical power is transmitted from said central office to said interface unit in parallel over said pair of transmission wires and a return path between said power sources and said electrical circuit is provided by earth ground.

An arrangement for transmitting of electrical power from a telecommunication switching office to a remote customer interface unit interconnected by a communication circuit comprising a pair of wires extending between said switching office and said remote customer interface unit and terminating at said interface unit in a transformer coil having a center tap;

• the power transmission arrangement comprising a power source having output terminals connected to said wires at said switching office for supplying power to each of said wires separately and a ground terminal connected to earth ground, power converter means having an input terminal connected to the center tap of said transformer coil at said interface unit and having a ground terminal, and filter means connected between said ground terminal of said power converter and earth ground for preventing the passage of signals of predetermined frequencies.