Device at a telephone subscriber terminal for disconnecting one out of two alternately and automatically connectable substations by the exchange in case of an undesired loop closure in one of these substations

Read the whole patent

Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

Why it's free to use

• Filed April 11, 1986 and granted February 8, 1989. A European patent lasts at most 20 years from filing, so its term ended April 11, 2006.
• A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by October 11, 2011.
• We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.