公开(公告)号：JPH11239233A

公开(公告)日：1999-08-31

申请号：JP31709898

申请日：1998-11-09

Applicant: LUCENT TECHNOLOGIES INC

Inventor： HOLLENBACH KEITH E ,  LATURELL DONALD R ,  WITMER STEVEN B

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

Abstract: PROBLEM TO BE SOLVED: To control the current through a DC terminal device by supplying a control voltage in order to control a voltage controlled current source(VCCS) as the function of a prescribed voltage. SOLUTION: When a control circuit 14 is in a fixed impedance mode, a chip/ring DC voltage received from a line filtered by a low-pass filter 52 is impressed to a multiplier 58. At this multiplier 58, the voltage is amplified by a DC terminal correction coefficient from a DC terminal correction coefficient 56. In the fixed impedance mode, the control. voltage for a VCCS 12 on an output line 40 is the corrected appropriately proportional value of a chip/ring voltage received through the line. When the control circuit 14 is in a fixed current mode, the fixed DC voltage is loaded through a switch 60 to the output line 40. Therefore, the DC control voltage impressed to the output line 40 for controlling the VCCS 12 is fixed.