FOERFARANDE Før detection of the farlig LINJESPAENNINGAR OEVER A TVAOTRAODIG Linjé.

摘要

PCT No. PCT/SE83/00464 Sec. 371 Date Jun. 29, 1984 Sec. 102(e) Date Jun. 29, 1984 PCT Filed Dec. 20, 1983 PCT Pub. No. WO84/02625 PCT Pub. Date Jul. 5, 1984.A method of detecting hazardous line voltages over a two-wire line for transferring digital information. At one end, the line is terminated by a hybrid coupler (G) and an apparatus for adaptive echo elimination. This apparatus generates a digital signal (d) constituting an unambiguous measure of the difference between the line impedance (ZL) and the hybrid impedance (Z). This signal is compared with two digital limiting values (d1,d2) an alarm being given should either these two values be reached or exceeded.