Ringing circuit
CA 1268872 C · Owner: The General Electric Company, Plc · Inventors: Robson, Michael Arthur Charles; Cross, Peter Andrew
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Ringing Circuit, The invention concerns an electronic ringing circuit for telephone systems. A capacitor is connected to the centre tapping of a first coil inductively coupled to a transistor-controlled supply line. The other side of the capacitor is connected to the junction between two switches each switch being connected via an induction coil to one end of the first coil so that when the switches are switched in opposite senses load current is drawn in alternate directions from the capacitor.
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 May 8, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 8, 2007.
- 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.