公开(公告)号：US3423709A

公开(公告)日：1969-01-21

申请号：US3423709D

申请日：1966-06-27

申请人： ELECTRONIC COMMUNICATIONS

发明人： LUGTEN LEO K

IPC分类号： H01F30/10 ,  H01F15/00

CPC分类号： H01F30/10

公开(公告)号：US3562439A

公开(公告)日：1971-02-09

申请号：US3562439D

申请日：1968-06-24

申请人： ELECTRONIC COMMUNICATIONS

发明人： LUGTEN LEO K

IPC分类号： H04Q1/50 ,  H04M1/50

CPC分类号： H04Q1/50

摘要： A telephone inband signalling system converts first and second DC signal levels by detecting a change in either direction between the signals to produce a voltage of predetermined time duration which exceeds the time between dial pulses. This latter voltage is employed to simultaneously (a) short the voice path, thereby preventing feedback to the calling party, and (b) enhance the tone of a 2600 hz. oscillator. The oscillator is then onoffed in response to the dial pulses coming over the input. At the end of the conversation, a muted 2600 hz. tone is continuously transmitted indicating an idle line.

公开(公告)号：US3514721A

公开(公告)日：1970-05-26

申请号：US3514721D

申请日：1966-12-30

申请人： ELECTRONIC COMMUNICATIONS

发明人： LUGTEN LEO K

IPC分类号： H03C1/54

CPC分类号： H03C1/545