Still getting info on this from from another tech. All I know so far is the system is a Nortel. I suspect a MICS or BCM 50 (not my customer, yet).

Customer just switched from copper lines to fiber from the under- build company, and now the system won't ring. Tech measured 47 volts incoming, which won't ring the system. After bumping up to 52 volts, then the system does ring. Are these line cards that sensitive?

Thanks.
Jim

Yes, they are. I've also had that same issue with a non-Nortel special type of Line Sharing Device. When I called the company that made it, I was told to take it apart and install a 9 volt dc battery in line with the power supply. Really? Better idea...change the LSD device.

Hmmm wasn't ring generator 90 volts back in the day? Just wondering if I'm losing my mind?

Yep (off course you sill might be losing your mind , John )

47 and 52 sounds like DC line voltage , does the tech know to mesure ring voltage as AC ? somewhere around 90 vac is what I would be looking for

Yup. Busted! Ha. I meant to post a follow up, but now I better straighten myself out.
Don't know what I was thinking of. The other tech is from another company, and he's been around a long time. He knows his stuff. But he doesn't do much Nortel work, so he called me while he was enroute. I think he also meant 90 volts AC ringing, but his mouth said 52 volts. And I was caught off guard and, . . . well, the mind is a funny thing. (at least mine is). I ran with the 52 without thinking. Gosh, I can't even blame this on the millenials.

And the follow up: The under-build company bumped up the ring voltage for this site and everything is ok. Apparently they can do this on a site by site basis.

Jim