On 01 May, 2006, at 10:38, TuskenTower wrote:
While reading articles about emergency recovery (after Hurican
Katrina), I came across some interesting information about the power
capacity of the local central offices that serve telephone lines.
Central offices are equipped with battery backups and (maybe) backup
generators. During an emergency, without power these COs can last
for
a some days (I'm hoping some is more than 7 days).
Maybe we should be asking for FIOS _and_ POTS (plain old telephone
service).
I don't know exact numbers these days for ALL CO's, however primary
switching centers
maintained a full set of batteries and standby-generators with 7 day
fuel supply on site and 15-30 day supply within a 6 hour delivery
distance.
[Historically they were 9th and race and 24th and South, but I also
know that Evergreen (38th and Chestnut) is similarly equipped now.]
The classic POTS system carries 48v DC on the lines - virtually all
the time. There is, or at least there was, a special number one
could dial which would allow tapping the battery directly, used
routinely by field linemen back in the days of Ma Bell for powering
soldering irons while up on a pole! This 48 volt current is supplied
by the batteries "in the basement." They are on-line all the time,
under constant "trickle charge" -- basically a submarine system. In
the event of a mains outage, a stand-by generator would kick-in and
spin up within 15 minutes to keep the charge up. (We're talking
about a stand-by generator here the size of a 40 foot trailer.)
Historically, 9th and race simply would pull the plug on the Mains
once a month and run on the Stand-by system for a 4-12 hour period
as part of "standard operating procedures."
How those systems have evolved over the past 25 years is hard to
say. Minimally, if one takes Evergereen as an example, the power
requirements went from powering equipment spread out over 6 floors
to powering equipment on less than one floor. So, theoretically, the
generator and tanks they have installed there will last a LOT longer
than in the past. (Note that the Verizon Mobile operation at 40th
and Chestnut has a completely separate stand-by generator capacity.)
The real question about Fibre based systems is how is the equipment
"in the loop" powered. Any kind of repeater, switch or similar
device in the loop outside the CO needs to be powered.
I know that one can buy 48v DC powered gear from Cisco and other
vendors. DEC used to sell a 48v powered Alpha (the 1000) which only
just last year (2005) went off the "able to purchase replacement
units" list from HP.
One interesting question about FIOS would be -- how does it (if it
does) qualify for "life-line" service? "Life-line" service is a
specific tariff with the PUC available to elderly, disabled and
similarly defined individuals. I don't know the specifics of the
tariff, and it may be only a "low-cost," not "level of service"
definition.
T.T.F.N.
William H. Magill
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whmagill@gmail.com
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