[sdiy] -48V dc/dc converters

[Paul Schreiber]

->
> does anyone know anything about -48V dc/dc converters? I have several here

-48V is the "industry standard" voltage for telephone central offices. All rack-based electronic
in the telephone industry runs off of a -48V feed.

For 100 brownie points: why is it a "negative" voltage instead of a positive one? The 48V comes
from 1920's wet-cell battery technology.

Paul S.
was designing phone stuff in a previous life