Telephone ringer isolator

Details Telephone ringer isolator Telephone ringer isolator

1976-01-12

1977-05-03

Claffy, Kathleen H.

179 84A, H04M 1300

Patent

active

040216179

ABSTRACT:
A telephone ringer isolator for isolating ringers and extending ringing range on a multiparty telephone line or for range extension only on single party lines is disclosed. The circuit includes a detector circuit for detecting the direct current superimposed on an alternating current ringing signal. A pair of biasing circuits for transistors are enabled by a properly poled ringing signal appearing between tip and ring conductors. When the transistors are enabled, a capacitor is charged to trigger a silicon-controlled rectifier. When thus fired, the silicon-controlled rectifier enables a diode bridge gate to connect the ringer between one side of the telephone circuit and ground potential. Isolation between the input and output terminals is provided by the high collector resistance of the gating transistors.

REFERENCES:
patent: 3471651 (1969-10-01), Saia et al.
patent: 3846644 (1974-11-01), Takagi et al.
patent: 3848140 (1974-11-01), Guermeur et al.
patent: 3916111 (1975-10-01), Ott
GE SCR Manual (fifth edition), "AC Phase Control", p. 231, (1972).

Affiliated with

Also associated with

Rating

Telephone ringer isolator does not yet have a rating. At this time, there are no reviews or comments for this patent.

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

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-346840