Frequency responsive selective ringing circuit
OwnerPhilip J. Del Monte, Jackie L. Vanweyinventors
Life of this patent
Estimating the term…
Abstract
A frequency responsive selective ringing circuit detects a selected one of a plurality of frequency-distinctive ringing signals applied on either the tip or ring conductors of a telephone line, distinguishes between the respectively different frequencies on a rapid cycle-by-cycle basis, and either applies the ringing signal to telephone equipment to ring the telephone equipment if the ringing signal is one which is selected, or rectifies the ringing signal and applies the rectified DC signal to the ringing circuit of the telephone equipment. The rectified DC signal will not ring the telephone because the DC signal is not conducted through a capacitor in the ringing circuit of the telephone equipment.
Claims19
A frequency responsive selective ringing circuit for ringing telephone equipment connected to a telephone line upon receipt of a predetermined one of plurality of frequency-distinctive AC ringing signals which have potentials on the telephone line that alternate at predetermined different frequencies and for preventing ringing of the telephone equipment upon receipt of any other frequency-distinctive ringing signals, the telephone equipment ringing only in response to a ringing signal conducted therethrough, said selective ringing circuit comprising in combination:
- rectifier and bypass means connected to the telephone line and operative for rectifying each of the ringing signals to a DC signal when not activated and for supplying the DC signal to the telephone equipment, and operative for electrically conducting the ringing signal to the telephone equipment when activated;
- and
- detection and activation means connected to the telephone line and to the rectifier and bypass means, and operative in response to the potential of the AC ringing signals for detecting a selected one of the frequency-distinctive AC ringing signals on the basis of one cycle of the AC ringing signal applied to the telephone line and for activating the rectifier and bypass means in response to the detection of the selected ringing signal.
A frequency responsive selective ringing circuit for ringing telephone equipment connected to a telephone line upon receipt of a predetermined one of plurality of frequency-distinctive AC ringing signals which have potentials on the telephone line that alternate at predetermined different frequencies and for preventing ringing of the telephone equipment upon receipt of any other frequency-distinctive ringing signals, the telephone equipment ringing only in response to a ringing signal conducted therethrough, the telephone line having a tip conductor and a ring conductor, said selective ringing circuit comprising in combination:
- rectifier and bypass means connected to the tip and ring conductors and operative for rectifying the ringing signals on the conductors to a DC signal when not activated and for supplying the DC signal to the telephone equipment, and operative for electrically conducting the ringing signal to the telephone equipment when activated;
- manually activated switch means connected to the tip and ring conductors and operative when manually activated to supply the ringing signals applied to a selected one of the tip and ring conductors;
- half cycle conduction means connected to said switch means and responsive to the ringing signals on the selected conductor for conducting only a half of an AC cycle of each AC ringing signal supplied by said switch means;
- timing means receptive of, and operative in response to the potential of, the half cycle of the ringing signal conducted by said half cycle conduction means for developing an output level signal related to the time width of the half cycle of the ringing signal conducted by said half cycle conduction means;
- mean connected to the timing means and receptive of the output level signal and operative in response to the output level signal exceeding a predetermined trigger threshold level for creating the control signal, the time width of only one of the half cycles of the plurality of frequency-distinctive ringing signals being sufficient to develop a sufficient output level signal from said timing means to create the control signal;
- set and reset means connected to said control signal creating means and said rectifier and bypass means and operative for establishing set and reset states in response to the control signal, said set and reset means supplying an activating signal to said rectifier and bypass means, said activating signal being either the presence or absence of activating energy to either activate or not activate said rectifier and bypass means, respectively;
- power supply means operatively connected to said selection and distinguishing means and operative in response to the half cycle of the ringing signal conducted by said selection means to develop power for energizing the set and reset means;
- and wherein:
- said set and reset means establishing one state in which either the activating signal is supplied or not supplied;
- and
- the control signal supplied to said set and reset means is operative to change the state of said set and reset means from that previously established.
Dependencies are inferred from the claim text.