Data transmission over long distance circuits
CA 1182935 A · Owner: General Datacomm Industries, Inc. · Inventors: Shum, Martin N.Y.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method and apparatus are disclosed which provide a common handshaking protocol for the 201 202 and 208 modems. This novel handshaking sequence trains up any echo canceller in the circuit, detects the presence of any echo suppressor and uses a conventional signal preamble in the presence of echo cancellers and a sacrificial carrier sequence in the presence of echo suppressors. As in the prior art a ringing signal is, applied to an answer modem in response to a signal from an originate modem, the answer modem is connected to the communication line after receipt of the ringing signal and an answerback tone, is transmitted from the answer modem to the originate modem after a period of silence …
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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 February 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 19, 2002.
- 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.