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GPO planset with external extensions
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3rd Jun 2019, 8:18 pm
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JohnBHanson
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Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 662
Re: GPO planset with external extensions
Some versions of planset use a transistor to detect the extension being off hook rather than a relay. This makes it polarity sensitive.
Also external extensions use need an earth to work ringing the main.
JohnBHanson
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