|
CA984067A
|
|
Line card circuit for dual station control
|
|
CA925230A
|
|
Line card
|
|
US3758729A
|
|
Line card circuit for dual station control
|
|
US3746795A
|
|
Long line adapter circuit usable with increased power supply
|
|
US3739099A
|
|
Long line adapter circuit
|
|
US3649772A
|
|
Line card circuit for a key telephone system
|
|
US3647983A
|
|
Key system line card circuit
|
|
US3626101A
|
|
Loop extender for subscribers connected to a central office by abnormally long telephone lines
|
