That is the normal voltage for a DC message waiting lamp.

https://www.sandman.com/messwait.html

From Sandman's site:
You can measure this voltage yourself if you have a better quality DC voltmeter (that presents a high resistance). Without message waiting, you will read 24 or 48 volts (or so) on an idle line. With message waiting, you will see a constant or interrupted (if the message waiting light flashes) 90 to 140 volts. If you only see this high voltage when there's a message waiting, you should have no problem using a NEON message waiting light on your system.


~edit~ I only caught the 3rd page, if you say there are no messages I guess it's something else.

Last edited by ttech; 11/14/15 11:18 PM.
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