Inbuilding telephone communication system
CA 2121602 A1 · Owner: Lee, William Chien-Yeh · Inventors: Lee, William Chien-Yeh
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An inbuilding communication system is described for providing telephone communication between sets of portable telephone (58) located in different areas (13-15, 17-19) of a building (12 or 16) wherein each set of portable telephones is assigned a substantially identical set of frequencies. The various areas (13-15 17-19) , are separated by building structure which attenuates radio signals. Each area is provided with a set of at least two antennas (54-56, 64-66, 74-76, 94-96, 104, 106, 108 114, 116, 118) the number, and position of each antenna being chosen such that the radio signals transmitted from such antennas are attenuated below a predetermined level from passing through the …
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
- Filed November 19, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 19, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 19, 2014.
- 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.