I cannot find a FDDI concentrator that runs on -48 VDC. Is there a
product I've missed? This shortage of DC-powered concentrators might
explain some of the transient outages during power problems at MAE-East,
perhaps?
The FDDI concentrators at MAE East (along with all the other AC-powered
infrastructure equipment) are powered by a UPS with at least 5 hours of
battery power. In addition, all customer equipment co-located at the
1919 Gallows P-1 MAE facility is powered by the UPS.
Here's a note from the facilities manager for MAE East on the subject of
power: