casey@well.sf.ca.us (Kathleen Creighton) (08/17/89)
I saw "Surviving the Big One" produced by KCET (PBS) in Los Angeles and
narrated by an LA fireman. One of the statements he made was that in the
event of a major earthquake which disrupts local phone service, we would
still be able to call *out of state* via pay phones. He recommended,
therefore, that California residents make use of (and let other people in
the family know about) an out-of-state contact who would then relay
information to others calling in.
As a San Francisco resident, this whole problem of communication in the
event of a major earthquake concerns me but I have *never* heard of the
supposed availability of pay phone communication in such event. Can
someone clear this up for me?
(As an aside, he also said that the telco can only tolerate 10% of its
pay phones being offhook at the same time so when you see a pay phone
offhook after an earthquake, hang it up.)
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[Moderator's Note: I am not sure why the *in-state/out-of-state* distinction
was made. Did the commentator somehow feel that central offices handling
long distance calls were somehow more immune to earthquakes or other problems?
And likewise, why did he think payphones were more reliable? A payphone
inside a building which has collapsed is just as damaged as a private phone
therein. The wires leading to/from them are as easily damaged; by an earthquake
at least if not necessarily human vandals.
Regards hanging up phones left off hook, that is a gracious thing to do.
All telcos are able to provide simulataneous service to only about ten or
fifteen percent of their customers at one time; and an even smaller number
can be offered dial tone at the same time. This is not a condition attributable
just to coin phones. When all circuits/switching equipment/dial tone generators
are busy, other customers sit with a 'dead' phone at their ear waiting.
Actually, the worst thing anyone can do in a time of national emergency
is jump on the phone. Stay off if possible. The night Martin King was
asassinated in April, 1968, nearly everyone in the Chicago-Monroe CO went
off hook at the same time. It damn near ruined the switch, which never did
work right after that. Remember, stay off the phone so that people who must
use it for emergency duties can do so without delay. If necessary, the CO
*can* shut off service to all but emergency numbers if desired. On Pearl
Harbor Day, Sunday, December 7, 1941, the (then mostly manual) phone system
in Chicago was so overtaxed that beginning at 1:00 PM that day the
operators answered everyone who went off hook by saying "Emergency calls
only! No other calls are being handled now..." And until about 10 PM that
night, *no one* could use the phone except as emergencies dictated. PT]dl@mthvax.cs.miami.edu (David Lesher) (08/19/89)
> Actually, the worst thing anyone can do in a time of national emergency > is jump on the phone. FTS was created for this very reason. Seems during the height of the Cuban Missile Crisis, JFK couldn't get a dial tone, so FTS used excess capacity at four (I think) rural CO's, one of which was in northern MD. With it, of course, you CAN get a dial tone. You just can't get a call to connect, or if it does, you can't hear. -- Flash! Murphy gets look and feel copyright on sendmail.cf {gatech!} wb8foz@mthvax.cs.miami.edu (305) 255-RTFM
geek@mit-amt.media.mit.edu (Chris Schmandt) (08/20/89)
At least for AT&T, it seems to be policy to provide greater access
for *outgoing* long distance calls from an emergency area (specifically,
recent CA earthquake) than incoming. The logic is that if a family
gets news out then relatives in other areas can pass it on to each
other without straining the network node in the emergency area.
Traffic quotas can be set, according to destination, for example,
at each of the 100-odd 4 ESS's. In other words, your local node
(Bent Street, Cambridge) knows to let only some fraction of the calls
towards the node in question (say, LA) through, and signals busy locally
without bothering the distant node.
Such decisions are made by humans at the NOC (Network Operations Center),
and implemented in the routing tables in each of the 4ESS's. I guess
this is somewhat easier now that the network is no longer heirarchical.
I was told the above{during a recent visit to the NOC. (amazing place,
never turn down a chance to visit it!)
chris