Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1997-08-28
2000-10-17
Isen, Forester W.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379324, 379399, H04M 1900
Patent
active
061343234
ABSTRACT:
A telecommunication system has a supply circuit to supply power to a telecommunication line. The telecommunication line is connected to a telecommunications subscriber device. The supply circuit has a first electronic impedance that is connected between a first voltage reference terminal and a first wire of the line, and a second electronic impedance that is connected between a second voltage reference terminal and a second wire of the line. The first electronic impedance has a first transistor, and the second electronic impedance has a second transistor. The supply circuit further has a first impedance multiplying circuit with a third transistor, and a second impedance multiplying circuit with a fourth transistor. The first impedance multiplying circuit multiplies the impedance of the first electronic impedance, and the second impedance multiplying circuit multiplies the impedance of the second electronic impedance. In a current path between the first voltage reference terminal and the second voltage reference terminal, main current paths of the first and third transistors, and of the second and fourth transistors are connected in respective series arrangements.
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Isen Forester W.
Saint-Surin Jacques
U.S. Philips Corporation
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