公开(公告)号：CA2469329A1

公开(公告)日：2001-04-08

申请号：CA2469329

申请日：2000-10-04

Applicant: LUCENT TECHNOLOGIES INC

Inventor： SMITH LANE A ,  FISCHER JONATHAN HERMAN ,  ZHU WEILIN ,  LATURELL DONALD RAYMOND ,  TOTH MICHAEL S ,  HOLLENBACH KEITH EUGENE

IPC: H04M11/06 ,  H04M19/00

Abstract: The present invention relates to a line powered COder/DECoder (codec). The codec is comprised of a fine powered analog-to-digital converter and a line powered digital-to-analog converter. A DC current measurement module is provided to determine an amount of current available for use from a telephone line in an off-hook condition. The analog-to-digital converter and the digital-to-analog converter are each adapted to be maintained in a reset condition when the DC current measurement module determines that insufficient current is available from the telephone line in the off-hook condition.

公开(公告)号：CA2250958C

公开(公告)日：2001-01-16

申请号：CA2250958

申请日：1998-10-20

Applicant: LUCENT TECHNOLOGIES INC

Inventor： HOLLENBACH KEITH EUGENE ,  LATURELL DONALD RAYMOND ,  WITMER STEVEN BROOKE

IPC: H04M19/00 ,  G05F1/46 ,  H02J1/04 ,  H04B3/02 ,  H04M1/738 ,  H04M1/76 ,  H04Q3/42

Abstract: A DC termination device particularly adapted for use in a device coupled to a two wire telecommunications system. The termination device controls the tip-to-ring current through the telecommunications device by means of a voltage controlled current source. The control voltage for the voltage controlled current source is provided by digital signal processing of the tip-to-ring voltage such that the tip-to-ring current is linearly proportional to the tip-to-ring voltage when the voltage is below a specified threshold level, but is maintained constant when the tip-to-ring voltage is over the threshold voltage. Preferably, the constant current is the minimum adequate current needed for operation.