Recently a friend discovered an extra active phone line in his San
Francisco apartment. To identify the mystery line, we dialed out on
it and the caller ID for it contains the name of a stranger who lives
a block from my friend. My friend is pretty sure that the stranger
has never lived in my friend's apartment building.
My guess is that the stranger's phone number works just fine at the
stranger's home, and that (perhaps years ago) ATT accidentally
connected the stranger's line to my friend's apartment via a wiring
error in the large ATT neighborhood wiring box that sits nearby on the
street. We cut the wire at the jack in the apartment so my friend
wouldn't use the stranger's line by accident. We haven't yet
contacted the stranger a block away, but we might do so.
I'd bet that this sort of wiring error happens regularly, and that the
phone company and the two subscribers in question don't notice it.
Have you ever heard of a wiring error of this sort? Could I be
mistaken about what's going on with the stranger's phone line?
[TELECOM Digest Editor's Note: We hear of this error quite often. It
is an error in multiples open on the same cable run. It most often
happens in older inner-city neighborhoods (i.e. Chicago, New York,
San Francisco) where the telephone cables go back many generations or
even a century or more, and typically in older buildings where at
some point in the past or maybe even now, there is a large, common
block or 'head' somewhere in the building with a large number of
phone terminations in one place. In telco's defense, they could not
begin to run a pair of wires to _everywhere_ and _everyone_ who has
phone service. So they run cables with hundreds of wires in each cable
around neighborhoods then splice open the cable at each location where
one or more phones are to be located. This is supposed to be a telco
SECRET and that makes it a SECURE system. Telco does not talk about
it to the public very much. So let's say we have cable #905 running
through the Haight-Ashbury neighborhood, and pair #6097 (of that cable)
serving your house.
Now when your phone was first installed, maybe the inside plant
decided to assign some other pair of wires, but the outside plant (a
different bunch totally) gets to your house to do the work and he
finds some screwed up mess of wires in your basement or wherever the
termination box is located so he decides to find some other idle pair
of wires, let's call them #6097 as above. We _suppose_ he at least
tested the pair to make sure they were idle, but who knows. When he
chose that pair he is supposed to consult a directory or map of the
cable-run and go to every other place on the 'run' where the cable had
been terminated, or spliced-into and 'open' them up or remove them
from any inside terminations along the way. He is then to note on this
map, or computer printout or whatever what he has done. "I hooked
user to pair #6097 on cable 905." Normally that would mean the 'red
and green' wires of the two-wire pair. Its a kind of 'musical chairs'
situation: half as many actual wires as there are telepone users and
instruments; keep swapping the pairs around as needed, make sure no
user gets left without a working 'pair'.
This gets sufficiently complex that the general public knows nothing
about it so telco claims and advertises it is SECURE. Now the end user
goes along, la-tee-dah, using his phone, all just fine. Telco does not
bill him for his calls based on his _telephone number_ (which we will
refer to as the 'commonly known as' name for those wires on cable 905
and pair 6097.) They bill him for the calls on that cable and pair
number. Your '_phone number_' is just the commonly used alias for those
Now one day, telco user is snoopy and discovers a 'yellow and black'
wire terminated in the box on his wall, apparently going nowhere. If
he knew about this sort of thing, he would know that yellow/black
wire(s) were actually pair 6098 on the same cable. He hears dial tone
because that pair of wires (the multiple) had not been properly
terminated (or clipped and disconnected) from his neighbor somewhere
else on the cable run. Or maybe, the lazy installer had 'borrowed'
the other half of the 6097/6098 combo from the neighbor to start with.
Typically a residence gets _two_ wire pairs ([red/green][yellow/black])
to start with, but in older very transient neighborhoods the phone
company records get confused and telco gets short of working wire
pairs so sometimes pairs get swapped around and borrowed from, and
these 'open multiples' (see above) get mixed up.
That, in a nutshell from the nut-emeritus here in Kansas, is how your
friend came to discover a stranger's phone active in his apartment.
Your friend, being the benevolent sort, would't dream of hooking up
a phone to that 'stangers wire pairs' and making any calls on that
line. If your friend used that 'strangers wire pairs' to make any
phone calls, either naughty or nice which brought the police or the
phone company bill collectors, they would wind up going to the
Stranger's door seeking recourse. That's because telco's SECRET and
SECURE system identified the Stranger as the phone call-maker. If the
Stranger called telco to complain about the dozen or so 900 calls on
his line, the telco service-rep (Miss Prissy) would wring her hands
and assure Stranger that he 'must have made the calls'. If police
'dumped the logs' on the PHONE NUMBER they'd also make certain
assurances to Stranger if you get my drift (although we do not expect
anything better of police who probably talked to Miss Prissy also).
Telco's records are correct; telco does not make mistakes, their
ways of doing business are quite SECURE.
So it _can_ be a serious problem unless everyone does their job
correctly; ie. outside telephone installers making _sure_ the wire
pairs are all correct, with no open multiples along the way. You do
not see this problem much in newer developments or neighborhoods with
mostly single houses, etc, where telco records are newer, 'more comp-
uterized', or better kept. It is almost always a problem in older
neighborhoods with people stacked on top of each other, and a century
of phone service, etc. By the way, if your friend were the perfectly
evil type person, he would make a nice looking 'tap' and place it
on the Stranger's wire pairs and listen to it forever, or if Stranger
had a dial-up modem on that line, watch his modem calls. That's often
times how police do it. PAT]