Ringing detector for use by the deaf
AssigneeBell Telephone Laboratories, Incorporated
InventorRichard G. Sparber
Life of this patent
Estimating the term…
Abstract
A ringing detector circuit for use by the deaf which may be connected between the tip and ring conductors (11, 12) of a subscriber set to cause an incandescent lamp (40) to flash to half brightness when ringing voltage is applied to the line. Closing a manual switch (22) allows the lamp (40) to burn at half brightness when the phone is not ringing and to flash to full brightness when the phone is ringing.
Claims11
A telephone ringing detector circuit connectible between an illuminating device and a source of alternating current and to a telephone line, said detector circuit comprising:
- first circuit means including first rectifier means connected between said illuminating device and said source for supplying current to said illuminating device only during first half cycles of said alternating current for energizing said illuminating device to a first level of illumination;
- and
- second circuit means including second rectifier means and also connected between said illuminating device and said source operated responsive to ringing voltage on said line for supplying current to said illuminating device also during second half cycles of said alternating current for energizing said illuminating device to a second, higher level of illumination.
A telephone ringing detector circuit comprising:
- a first input terminal for receiving telephone ringing voltage;
- a second input terminal for receiving an alternating current;
- an output terminal;
- first circuit means including first rectifier means connected to said second input terminal and said output terminal for supplying current to a load only during first half cycles of said alternating current received at said second input terminal when said load is connected to said output terminal;
- and
- second circuit means including second rectifier means connected to said second input terminal and said output terminal and operated responsive to said ringing voltage received at said first input terminal for supplying current to said load also during second half cycles of said alternating current receiving at said second input terminal when said load is connected to said output terminal.
Dependencies are inferred from the claim text.