Tone receiver
CA 1045733 A · Owner: Houston Natural Gas Corporation · Inventors: Hawkins, Donald W.; Ebner, Theran L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A tone receiver for connection to a telephone line at the station end for responding to a predetermine tone frequency in which the receiver has a multiple frequency selectable channel for allowing the receiver to respond to only one of a plurality of input tone frequencies. Circuit means are provided for comparing the input tone frequency with the output of the selected frequency for insuring that the receiver is responsive to only a predetermined input frequency. A programming circuit is provided for allowing the receiver to sample the input tone frequency only during a predetermined time interval. Storage means are connected to and actuate the receiver output when a predetermined number …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted January 2, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 2, 1996.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.