I thought it would be a good idea to spell out exactly why the phones were
dead before rumors ran rampant and someone looses their head. Besides, it's a
always nice to give credit where credit is due.

PacBell pulled the plug on us. To their credit, they did say, "oops". If you
are curious about the how and why, here's some (lengthy) details. If not, then
type D now...

Our telephone system is connected to the world through three T1 links. Each T1
link handles 24 channels of digitized voice. Physically a T1 link consists of
2 twisted pair and is indistinguishable from two plain ordinary analog
telephone lines (the kind that you use in your house). Telephone service
people (PacBell) are supposed to mark "special" circuits, like T1 links, with
tags and/or red plastic buttons where  these circuits appear in underground
and overhead connection blocks. They don't always do that and they don't
always pay attention to the markings even if they are there.

You may have noticed the PacBell trucks and personnel working along Montague,
McCarthy, Sycamore and Barber Lane over the last few days. They are installing
fiberoptic cable and Milpitas is upgrading the equipment in their "central
office" (CO). Somewhere in the miriad of streets, cables, poles and connection
panels, a technician took it upon his/herself to disconnect a few wires
(probably to move them to a different location). I can imagine they were
thinking "it's only 2 wires, nobody will notice." In our case, we lost 24
connections on each of the three T1's that were disconnected.

One would think that if a circuit were disconnected for a few seconds then
reconnected, we might see a hiccup in service but it shouldn't shut down the
phones for good. I expect that if PacBell had modern equipment this indeed
would be the case. They don't, so it isn't. The CO isn't smart enough to
recognise that a T1 line has 24 channels on it so it treats a T1 as 24
separate and independent circuits. If the CO trys to route a call to a circuit
(or one of the T1's 24 channels) and can't get through because of errors, it
will disable that circuit and try a different one. If our telephone system is
down or the T1 circuits are down, one incoming phone call will cause the CO to
try all available circuts (therefore all 24 channels on the T1) and disable
each one in turn, all within a few seconds. Likewise, it disables our
outgoing trunks if there are too many errors detected.

Neither is the CO equipment smart enough to recognise that a circuit has been
re-established. There is all kinds of signalling on a T1 line to indicate
quality of service and the receiving equipment at the CO certainly knows the
line is up or down, it just doesn't notify the call routing equipment. I
suspect that the antique call router is not able to accept this kind of info
from other signalling devices. This means that when a circuit is disabled, it
can only be renabled by a tech at PacBell. So, we have to call them to tell
them that our lines are down and they have to figure out who we are, where our
lines are, how to test them then how to turn them back on. This usually takes
an hour but may take longer depending on who is working at the CO and whether
or not they know what they are doing.

Is this an isolated incident? Nope. Has it ever happened before? I don't think
the trunk lines were severed before, but the CO has frequently disabled our
DID's and outgoing trunk lines because either the ROLM acted up or the power
in the building was interrupted for more than a few seconds. Will it happen
again? You can count on it. Is there something we can do about it? Yep, switch
service from PacBell to one of the other dozen or so local telephone companies
available in our area :).

ds