| 摘要 |
PCT No. PCT/SE95/00800 Sec. 371 Date May 8, 1996 Sec. 102(e) Date May 8, 1996 PCT Filed Jun. 28, 1995 PCT Pub. No. WO96/01015 PCT Pub. Date Jun. 28, 1995An apparatus interfaces with a subscriber line interface circuit (1) and protects the interface circuit (1) against overvoltages exceeding a supply voltage source supplied to the subscriber line interface circuit. The apparatus includes first and second diodes (DA1, DB1) having respective anodes connected to first and second input wires (A, B). The cathodes of the first and second diodes are connected to a positive terminal of the supply voltage source. The apparatus further includes third and fourth diodes (DA2, DB2) having cathodes connected the first and second input wires (A, B). The anodes of the third and fourth diodes are connected to a cathode of a thyristor (TAB). The anode of the thyristor, in turn, is connected to the positive terminal of the supply voltage source, and the gate the thyristor is connected to a negative terminal of the supply voltage source.
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