Data transmission systems
CA 1063269 A · Owner: Post Office (The) · Inventors: Kingswell, Leonard W.; Matthews, Oliver C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An electrical data transmission system employs a telephone line to transmit data from a subscriber data equipment to a telephone exchange data equipment when the telephone line is idle. A first idle line sensing means is associated with the subscriber equipment and is operable to connect the line to the subscriber equipment when the line is idle and to disconnect the line from the subscriber equipment when the line is busy. A second idle line sensing means is associated with the exchange data equipment and is operable to connect the line to the exchange equipment when the line is idle and to disconnect the line from the exchange equipment when the line is busy.
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 September 25, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 25, 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.