circuit that watches for phone ring and resets external device

visiperl · 2006-08-11T12:59:52+00:00

Hi all,I'm looking for either a circuit, kit or prebuilt device that will hookup to a phone line and when I dial that extension it will reset my DSLmodem and router.All I need it to do is sense the incoming ring voltage momentarilyinterrupt the power.Does anybody have any suggestions?Thanksvp

Aug 11, 2006 21 Replies

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Gunther Mannigel 19 years ago

snipped-for-privacy@gmail.com schrieb:

Ring indicator line of an old modem?

cheers Gunther

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Ross Herbert 19 years ago

Connect a 2uF, 250V capacitor in series with the ac inputs of a bridge rectifier and connect this arrangement across the telephone line. The

+ve output from the rectifier connects to MT2 of a suitable TRIAC (I used a BTA04-600) and MT1 connects to one side of a relay coil (I used a DIL 48V dc relay with coil R = 7800 ohms). The other side of the coil connects to the -ve terminal on the bridge rectifier. Across the coil connect a 220uF 63V electrolytic with appropriate polarity. A bi-directional trigger diode (I used a DB3) connects between MT1 and G of the TRIAC. Works like a charm.

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