Key telephone system

Details Key telephone system Key telephone system

1978-03-21

1980-01-15

Brigance, Gerald

179 15BB, H04Q 518

Patent

active

041840542

ABSTRACT:
A key telephone system is provided which comprises: a plurality of key telephones; a key service unit; a plurality of transmission paths each including a first transmission cable for transmitting a voice signal between the key telephone and key service unit, a second transmission cable for transmitting a first control signal from the key telephone to the key service unit, and a third transmission cable for transmitting a second control signal from the key service unit to the key telephone; first, second and third transformers of which the primary windings are connected to the key telephone and the secondary windings to the first, second and third transmission cables; and fourth, fifth and sixth transformers of which the primary windings are coupled with the first, second and third transmission cables, respectively, and the secondary windings to the key service unit. The key telephone system is further provided with a seventh transformer of which the primary winding is connected to the key telephone, and the secondary winding between the center taps of the secondary windings of the first and second transformers and an eighth transformer of which the primary winding is connected between the center taps of the secondary windings of the fourth and fifth transformers and the secondary winding to the key service unit.

REFERENCES:
patent: 3604857 (1971-09-01), Opferman
patent: 3843845 (1974-10-01), Ridley
patent: 3973085 (1976-08-01), Shiff
patent: 3975594 (1976-08-01), Guntersdorfer
patent: 4046972 (1977-09-01), Huizinga et al.
patent: 4061887 (1977-12-01), Kasson et al.
patent: 4092501 (1978-05-01), Suzuki et al.

Affiliated with

Also associated with

Rating

Key telephone system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Key telephone system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Key telephone system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1029161