Device for limiting the working voltage for mechanical switches in telephony includes terminals for connection to a telephone line, a connection and power supply branch for a control circuit extending from a first terminal, the branch having a first switch, the cathode terminal of a first Zener diode...http://www.google.fr/patents/US5448636?utm_source=gb-gplus-shareBrevet US5448636 - Device for limiting the working voltage mechanical switches in telephony
Device for limiting the working voltage mechanical switches in telephony
