Hook up a scope (digital?) put it on a relatively slow trace and trigger on the drop with some pre-trigger time set.
:Question for your guys experienced in telephone circuits... : :Every 30 minutes it looks like my on-hook voltage drops from 50VDC to :ZERO for a fraction of a second. : :It happens so fast I can't get an accurate read on it... but the :auto-ranging DVM drops from "V" to "mV" : :What is this all about? : : ...Jim Thompson
Do you have an externally monitored home alarm system?
Electronic switches (Aka computerized switches) do line scanning on a constant basis. That's probably it.
I remember I had my TS-22 hooked to my line for some reason and I'd keep hearing a burst of FSK. It was the voicemail indicator.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required