Frequency responsive party telephone line selection apparatus an

Details Frequency responsive party telephone line selection apparatus an Frequency responsive party telephone line selection apparatus an

1985-08-09

1987-10-20

Dwyer, James L.

Telephonic communications

Polystation line system

Call alerting

379180, 379181, H04M 1300

Patent

active

047019492

ABSTRACT:
An apparatus adapted to be coupled into a party telephone line for selecting a ringing signal transmitted on the line from among a plurality of possible coded ringing signals that could be transmitted on the line and for coupling the ringing signal to a telephone is disclosed. The apparatus comprises a rectifier coupled to the party line for providing a rectified ringing signal, a first switch having the rectified signal as an input for reversing the polarity of the rectified signal at selected times, a second switch coupled to the first switch for selecting either the rectified ringing signal or the ringing signal itself and a third switch coupled to the second switch for coupling the selected signal to a telephone coupled to the third switch. A control unit comprising a microprocessor is provided which evaluates the incoming ringing signal to determine its frequency and controls the first, second and third switches to route the ringing signal to the telephone if it is of the proper frequency after any necessary frequency conversion which is performed under control of the microprocessor. Frequency conversion is performed by appropriate control of the first switch coupled to the output of the rectifier.

REFERENCES:
patent: 3391253 (1968-07-01), Grandmaison
patent: 3626106 (1971-12-01), Greening et al.
patent: 4048448 (1977-09-01), Caniff et al.
patent: 4154987 (1979-05-01), Rosenberg et al.
patent: 4567330 (1986-01-01), Curtin
patent: 4587380 (1986-05-01), Curtin

Affiliated with

Also associated with

Rating

Frequency responsive party telephone line selection apparatus an does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Frequency responsive party telephone line selection apparatus an, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Frequency responsive party telephone line selection apparatus an will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1617137