Patent ID: 6516054
Filing Date: 2003-02-04
Classification: H04M

Abstract:
A method for adjusting current levels falsified by offset-current levels, the method which comprises:providing a subscriber line circuit in a digital telephone exchange, the subscriber line circuit including a high-voltage section and a low-voltage section, the high-voltage section mainly including line drivers and elements for a subscriber line indication, the low voltage section including a signal processor and serving essentially as an analog/digital interface and providing a 2-wire/4-wire conversion; measuring, in the low-voltage section, a level of an offset current when the offset current is present, the level of the offset current having a given mathematical sign; storing, in the low-voltage section, the level of the offset current with a mathematical sign opposite to the given mathematical sign for providing a stored level of the offset current; and adding, in the low-voltage section, the stored level of the offset current with the mathematical sign opposite to the given mathematical sign to a current to be measured for a correction when a current measurement is to be carried out during a normal operation.