[clug] Telephone line voltage

Francis Whittle fj.whittle at gmail.com
Sun Sep 5 22:15:28 MDT 2010

Steve and/or Keith,  could you explain (preferably  diagram) the test
setup you're using?  What exactly are you measuring the voltage across,
for example?

On Mon, 2010-09-06 at 10:45 +1000, steve jenkin wrote:
> A Telstra tech tested this line with their box-of-magic, and it doesn't
> flag any AC leakage. He was at a loss to explain or interpret the
> multimeter reading. [Beyond his training, I think.]
> Two different electronic multimeters have been used on the line.
> Both detect ~48V DC, both detect ~100V AC, mostly but not always.
> I've used my multimeter on my home line - same deal.
> Could ADSL RF frequencies (or other signals) be inducing apparent
> high-volt AC in the multimeter??
> I can't explain:
>  - not always there (but mostly)
>  - Telstra can't explain and isn't concerned. [Would you expect less]
> I'm inclined to think it's an artefact of the way modern electronic
> multimeters work... But that's not an explanation.
> I believe Keith chased Telstra further, to no avail.
> -- 
> Steve Jenkin, Info Tech, Systems and Design Specialist.
> 0412 786 915 (+61 412 786 915)
> PO Box 48, Kippax ACT 2615, AUSTRALIA
> sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin

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