Phone Systems Tutorial part II by The Jolly Roger
Part II will deal with the various types of operators, office
heirarchy, & switching equipment.
There are many types of operators in the network and the more
common ones will be discussed.
The TSPS [(Traffic Service Position System) ass opposed to This
Shitty Phone Service] Operator is probably the bitch (or bastard,
for the female libertationists out there) that most of us are used
to having to deal with. Here are his/her responsibilities:
1) Obtaning billing information for calling card or third number
2) Identifying called customer on person-to-person calls.
3) Obtaining acceptance of charges on collect calls.
4) Identifying calling numbers. This only happens when the calling
# is not automatically recorded by CAMA (Centralized Automatic
Message Accounting) & forwarded from the local office. This could
be caused by equipment failures (ANIF- Automatic Number
Identification Failure) or if the office is not equipped for CAMA
(ONI- Operator Number Identification).
Ask to speak to their supervisor... or
better yet the Group Chief (who is the highest ranking official in
any office) who is the equivalent of the Madame ina whorehouse.
By the way, some CO's that willallow you to dial a 0 or 1 as the
4th digit, will also allow you to call special operators & other
fun Tel. Co. #'s without a blue box. This is ver rare, though! For
example,212-121-1111 will get you a NY Inward Operator.
Every switching office in North America (the NPA system), is
assigned an office name and class. There are five classes of
offices numbered 1 through 5. Your CO is most likely a class 5 or
end office. All long-distance (Toll) calls are switched by a toll
office which can be a class 4, 3, 2, or 1 office. There is also a
class 4X office callen an intermediate point. The 4X office is a
digital one that can have an unattended exchange attached to it
(known as a Remote Switching Unit (RSU)).
The following chart will list the Office #, name, & how many of
those office exist (to the best of my knowledge) in North America:
Class Name Abb # Existing
----- ----------------------- --- -----------------
> 1 Regional Center RC 12
> 2 Sectional Center SC 67
> 3 Primary Center PC 230
> 4 Toll Center TC 1,300
> 4P Toll Point TP n/a
> 4X Intermediate Point IP n/a
> 5 End Office EO 19,000
> 6 RSU RSU n/a
When connecting a call from one party to another, the switching
equipment usually tries to find the shortest route between the
class 5 end office of the caller & the class 5 end officeof the
called party. If no inter-office trunks exist between the two
parties, it will then move upward to the next highest office for
servicing calls (Class 4). If the Class 4 office cannot handle the
call by sending it to another Class 4 or 5 office, it will then be
sent to the next highest office in the hierarchy (3). The
switching equipment first uses the high-usage interoffice trunk
groups, if they are busy then it goes to the fina; trunk groups on
the next highest level. If the call cannot be connected, you will
probably get a re-order [120 IPM (interruptions per minute) busy
signal] signal. At this time, the guys at Network Operations are
probably shitting in their pants and trying to avoid the dreaded
Network Dreadlock (as seen on TV!).
It is also interesting to note that 9 connections in tandem is
called ring-around-the-rosy and it has never occured in telephone
history. This would cause an endless loop connection [a neat way
to really screw up the network].
The 10 regional centers in the US & the 2 in Canada are all
interconnected. they form the foundation of the entire telephone
network. Since there are only 12 of them, they are listed below:
Class 1 Regional Office Location NPA
Dallas 4 ESS 214
Wayne, PA 215
Denver 4T 303
Regina No. 2SP1-4W (Canada) 306
St. Louis 4T 314
Rockdale, GA 404
Pittsburgh 4E 412
Montreal No. 1 4AETS (Canada) 504
That's it for now! More info to come Future update to the
Cookbook! Have fun! -Exodus-