How to Get Into a CO (March, 1985)
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By The Kid & Co.

Having spent a lot of time trashing outside the CO, I decided it was time to
see what was inside. The first idea that came to mind was to try and make my
own informal tour. This was impossible due to the magnetic lock on the door. So
my next thought was to arrange a tour legitimately; who would expect a phreak
to try that?

A call to the business office started me on my way. They in turn gave me the
phone number of the Public Relations people, who told me to send a letter to a
primary switching office in my area. I anxiously waited for several weeks. Then
one day I received an urgent phone call from the Telco while I was out.
Thinking it was Bell Security, I became nervous. I called back but the person
who called was out. So I had to wait. Sure enough he called back. I was very
relieved when he informed me that he was calling about the tour I had
requested. I was also surprised to find that he sounded like a reasonable human
being. We worked out some details and set up a date for the tour. I now had to
select the group to go with me and prepare some questions.

I could bring up to 10 people on the tour. My obvious first choice was my
phriend, The Shadow. The real problem was who else could I bring? I did not
want to take a chance on someone saying too much and thus creating a problem.
So I chose several others, sticking to people who were just interested in the
tour because they wanted to know what the CO was, but weren't smart enough to
ask embarrassing questions.

The Shadow and I spent several hours preparing questions to get the maximum
benefit from the tour. We found that those few hours we spent preparing
ourselves were well worth the time. We started with simple questions to which
we already knew the answers. These would lead to the more complex and specific
questions, without revealing our true identities as telecommunications
hobbyists.

After weeks of waiting, the day of the CO tour arrived. We were ready!
Notebooks in hand, ready to record the commentary, we drove the familiar route
to the CO. We looked nostalgically at the dumpster and thought, "No. Not now,
later." Upon arrival, we were forced to wait outside while our guide, the
system manager, was being notified. He finally appeared and greeted us
pleasantly. Much to my surprise, he did not look like a standard Telco
employee, for he did not wear the obligatory flannel shirt. We entered the
building and took the elevator to the switching room. I took control of the
situation by BS ing our guide while The Shadow copied down anything he could
find written on the walls, etc. We were shown a #1 Crossbar Tandem and the
ESS #1A, which were co-residents on the switching floor. We examined the
billing tape drives and asked several questions as to the nature of the tape.
After 20 minutes or so on the switching floor, he took us to the floor where
the wires came in from the outside. While on this floor we also noticed a TSPS
machine, of which he had little knowledge, since "that's AT&T." After asking a
few more questions and taking more notes, he gave me his number and told us to
call him if we had any more questions.

Some Facts

The tour was very informative. We had several misconceptions cleared up. The
first, and probably most important, was the mystery of the billing tape! Exactly
what does it contain? The tape contains records of the following types of
calls: 0+, 1+, and 7-digit numbers out of your local calling area. In other
words, they only record the numbers that you or someone else will have to pay
for (1+800, collect calls as well). The tapes are then sent to the billing
office, which handles the billing for both the local Bell and AT&T. According
to our guide, the ESS does not keep track of every digit dialed. This is not to
say that it can't be done, but that it would be impractical. His CO handles
well over a million calls a day, and if it were to keep track of all the digits
dialed, the storage requirements would be tremendous. Does the ESS print out a
list of exceptional 1+800 callers every day? The answer is no, the ESS does
not! But the billing tape does contain records of 1+800 usage, and that type of
processing may be done by the billing department, not the CO.

During the tour, we were introduced to the ESS#1A. Our ESS is running a #7
generic program. The #9 generic program is the revision that identifies the
number calling you before you answer. It consisted of two equipment racks, each
6x10 full of printed circuit boards and IC's. All of the boards were push-in,
pull-out for easy servicing. One might think from the description of the ESS
that we have given that it does not require much space. The ESS processor does
not require much space at all, but the equipment that interfaces the local loop
with the call processor requires quite a bit more. Unknown to most, the ESS #IA
consists of two independent processors that are constantly checking each other.
They perform diagnostics if discrepancies do occur. This is a technique similar
to the one used by the space shuttle's computers except that it is more
reliable. You cannot shut down the ESS and put a whole town out of touch with
the world just because the computers don't agree. The ESS is programmed via
magnetic tape drives. The ESS stores the information about its configuration
and information about your phone line (special features like call waiting, call
forwarding, speed calling, touch or rotary dialing) on two massive hard drives.

Fiber optics are in use! As my group discovered, they are being put on poles
all over the place. The cabling is called Light Guide and is made by Western
Electric. The transmission system used is called SLC-96 (Slick 96). This system
carries 96 simultaneous phone conversations on a single optic fiber. Our guide
unfortunately did not know more than the name of the system and its
capabilities.

How You Can Meet Your CO

You probably would like to know how you can arrange your own CO tour. You ve
spent all that time staring in, but now you're willing to meet all those nice
people inside. The first thing to do is to find a group to go with. The people
at the Telco are more likely to let a legit organization visit, rather than
just a random group of people. Having just one or two people show up will
really make them suspicious. Be sure to take along at least one responsible
person to make it look legit. Try groups such as the Boy Scouts, an Explorer
Post, a school class, a computer club, or simply come up with a
legitimate sounding name (not the Legion of Doom or the 2600 Club). This group
should consist of people who logically have an interest in the phone system the
Audubon Society might seem a little out of the ordinary. The group should be
interested in electronics. A bored group will want to move on quickly, despite
your interest. Don't take only phreaks, as the Telco may get suspicious. The
person who attempts to set up the tour should also have no record with Bell
Security, as a routine check might be implemented. Be sure to get a good mix of
technical/nontechnical people on the tour.

After finding such a group, you should contact the local telephone company's
public relations office. Companies are worried about their image, for people
tend to acquire an anti-big-business bias when they receive big bills. They
will jump at the opportunity to combat this prejudice, and will do their utmost
to ensure a tour, even over the objections of workers. Set up a mutually
convenient time for your appointment and let your group know.

Proper planning is the best way to maximize information gathering. Questions
should be thought out in advance. The questions should start out nontechnical,
gradually progressing toward the technical as the guide lets down his/her
guard. Be careful not to make the questions obviously phreak-oriented. Ask
about common knowledge and general interest subjects, such as equal access, the
AT&T split-up, fiber optics, and just how does my call get where it is going.
Remember, the guide thinks he is showing around another group of idiots.
Questions relating to phraud should be asked innocently, and with references
that you have heard about this terrible, dreadful subject in the popular media.
Questions about blue boxing should quote articles about general phreaking and
hacking. Newsweek articles and "$12,000 calling card bills delivered via UPS"
news stories. Remember, you don't want to put him on his guard. For better
results, spread your questions around for trustworthy friends to ask. Don't be
stingy for you don't want all the attention.

On the actual day of the tour, be sure to bring along notebooks. You will want
to record this event for posterity, and for your phriends. If the guide
comments on your note taking, just say you are going to write a report for
school or an article for your club's newsletter (sounds familiar?). Take down
any test or other numbers you see on the wall, but try not to "borrow" or you
could be in big trouble. We have heard, third hand, of some phreaks on a CO
tour who took whatever they could down their shirts, etc. After the tour, they
were taken into a room where they were forced to disgorge all they had phound.
It isn't worth the risk to steal.

On the tour, conduct yourself properly; you don't want to stand out. Resist the
urge to answer others' stupid questions yourself. Do not show off knowledge.
Only gently prod the tour guide on subjects you are interested in. The guide
will usually give you his number for further questions; be sure to keep it.
Leave a good impression so that fellow telecommunications hobbyists can tour
the place in the future.

These basic techniques can be used to get a tour at almost any location. Other
places you might consider are local AT&T Bell Research facilities, GE, Northern
Telecom manufacturing plants, or any computer center. On a tour you can easily
pick up information that is difficult or impossible to find otherwise. At the
very least you can get the type of switch your CO uses. For the most accurate
information on your telephone system, go right to the source, your local CO!