公开(公告)号：US3602800A

公开(公告)日：1971-08-31

申请号：US3602800D

申请日：1969-05-21

Applicant: BELL TELEPHONE LABOR INC

Inventor： FELDMAN DAVID ,  GOLEMBESKI JOHN J ,  RAO TADIKONDA N ,  WYNDRUM RALPH W JR

IPC: H04M3/00 ,  G05F1/00 ,  G05F1/60

CPC classification number: H04M3/005

Abstract: A coupler for attaching customer-owned equipment to the telephone network permits any customer signal below a prescribed signal level to pass without distortion or attenuation but linearly attenuates signals exceeding the prescribed level. The coupler measures the mean power of the customer''s signal and utilizes the results to switch the proper attenuating load across the line. The switch circuit of the coupler has a hysteresis characteristic to prevent distortion of the customer''s signal by repeated switching between different alternating modes when the customer''s signal has slight variations about the prescribed threshold level.

公开(公告)号：US3521005A

公开(公告)日：1970-07-21

申请号：US3521005D

申请日：1966-09-01

Applicant: BELL TELEPHONE LABOR INC

Inventor： DOW ROBERT J ,  WYNDRUM RALPH W JR

IPC: H04M1/50 ,  H04M1/26 ,  H03B5/20 ,  H03H7/10

CPC classification number: H04M1/50

公开(公告)号：US3460026A

公开(公告)日：1969-08-05

申请号：US3460026D

申请日：1967-05-08

Applicant: BELL TELEPHONE LABOR INC

Inventor： DOW ROBERT J ,  FELDMAN DAVID ,  LEE SAMUEL C ,  MITCHELL EDWARD S JR ,  WYNDRUM RALPH W JR

IPC: H01C1/12 ,  H01C1/16 ,  H01L49/02 ,  H01C7/00

CPC classification number: H01C1/16 ,  H01C1/12 ,  H01L49/02