Circuit for the protection of telephone lines
CA 1089005 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Dijkmans, Eise C.; Schoofs, Franciscus A. C. M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Arrangement for protecting telephone lines and electronic circuits connected thereto from overvoltages. A first pair of diodes clamp the voltage of each wire versus the supply voltages in cooperation with a current limiting impedance. A second pair of (Zener-) diodes separated from, the first pair by means of a current limiting impedance clamp, the forward "transient" produced across the first pair versus the same or slightly deviating supply voltages. -10-
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 November 4, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 4, 1997.
- 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.