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==Phrack Inc.==
Volume One, Issue Nine, Phile #9 of 10
Loop Maintenance Operations System
Written by Phantom Phreaker and Doom Prophet
Part I: A basic overview of LMOS
Part II:Mechanized Loop Testing
Loop Maintenance and Operations System (LMOS) is a telephone company
database that is a vital part in the act of repairing local loops (a customers
telephone line). When you call the Repair Service to have your telephone
service repaired, the information you give, as well as information and history
on your local loop is processed through the LMOS database. This file shall
examine several of the parts of LMOS, which is used by a number of different
bureaus. The bureau that you reach when you dial your repair service is called
the Centralized Repair Service Answering Bureau (CRSAB), and is usually
reached by dialing (1)+611 or sometimes a POTS (Plain Old Telephone Service)
number in areas where the X11 services aren't available. A CRSAB attendant is
who you will deal with when reporting line trouble. You will tell the
attendant the line number, and the types of problems you are experiencing on
that line. The attendant will file a report concerning the basic information
vital to line repair. Something called 'Front End Processors' form a
'real-time' interface between the customer reporting the trouble, and the
CRSAB attendant. 'Real-Time ' means that it is done on a continually changing
basis, (ex. while the customer is reporting the trouble to an attendant,
action is being taken.)
When a customer makes a trouble report to the CRSAB, the report is filed
and sent through the Cross Front End, which is a link from the CRSAB to the
LMOS system network. The trouble report is sent along a data link to the Front
End, where a BOR (Basic Output Report) is requested. BOR's include line record
information such as past trouble history and numerical values of MLT system
tests. MLT is Mechanized Loop Testing. As LMOS is responsible for trouble
reports, past trouble analysis, and other data related functions, MLT, which
is connected to LMOS through a minicomputer in the Repair Service Bureau known
as the MLT Controller, does the actual testing of subscriber loops. MLT
hardware is located in the Repair Service Bureau. This hardware is linked to
the LMOS system by way of an LMOS minicomputer, which may be in a remote
location or with the LMOS central processor. Test trunks connect MLT hardware
to the Wire Centers, which in turn connect with the subscriber loops.
The Databases of LMOS are connected via a high speed data link. The major
divisions of data handled by LMOS are listed below.
Past Trouble History- This information is contained within the
Abbreviated Trouble History (ATH) database and holds the most recent 40 days
of history.
The Trouble History (TH) database contains histories of troubles for the
day. This TH database is used to support TREAT (Trouble Report Evaluation and
Analysis Tool) reports.
Line Record- These bases contain info about the customer's telephone
circuit, whether it is POTS (for which there is a separate database), or SS
(Special Service). Special Services numbers can be up to 16 characters plus
the NPA or area code. The LMOS definition of an SS is any circuit having an
identifier that is other than 10 digit numeric with NPA.
Also, the Cable (CA), Associated Number (AN), Telephone Answering service
(TAS), and Central Office Equipment (COE) data bases contain line record
information as well.
Miniline Record- There is one Miniline Record database for each Front End
transaction processor. An example explaining this would be: A customer makes a
trouble report to the CRSAB. The data sent through the Cross Front end to the
Front End database, where a BOR is requested, is recorded and applied as
status by the Miniline Record database to the Front End base. This helps to
keep the LMOS Master Database in conjunction with the Front End bases.
Service Order History- This base contains a list of all lines changed
during the day. The list is used for construction of Miniline Records to be
sent to the front ends.
While there are many other databases within the LMOS system which serve a
variety of functions, the bases listed above are the major ones.
The telephone network is divided into two major pieces, the loop portion,
or the line from a Central Office to the customer premises; and the Toll
portion. This is the network that connects long distance offices such as the
Toll center and Primary center, and is also known as the Direct Distance
Dialing or DDD network. The LMOS database is customer and loop oriented. The
loop portion of the network is frequently altered and changed, as it is the
customer's link with the DDD network. These changes are tracked by LMOS. This
type of activity falls into two categories: Customer initiated service
requests (when a customer makes a request or trouble report), and Bell
Operating Company initiated plant changes.
'Plant' is the Outside Plant of cable which makes up the local loop. A
Customer initiated service request is for installation of new lines for the
customer. The Universal Service Order or USO is the record of all these types
of requests. USO's contain information such as customer listing, billing
section, service and equipment section, and the Assignment section, which
identifies the Central Office and outside plant (cable) facilities or lines.
A BOC initiated plant change is called a work or job order. This is when
the BOC serving the area make additions and rearrangements to loops to meet
customer requirements for service. Examples of work orders include the
following:
Cable Throw-This order is when a cable pair is added to assist an
existing cable in a high-growth area. This involves a change to the customer's
cable and pair number. Cable Throw Summaries are printouts from this type of
work order.
Area Transfer-This order is used when Wire Centers, or the point where
customer cable pairs branch out from, have to be balanced to compensate for
growth, as there will be a need for more subscriber loops. This often involves
the change of a customer's number.
Service Orders pass through a BOC interface program to add RSB
identifiers, which are repair unit numbers, needed by LMOS to translate data
to a USO format.
The Automatic Line Record Update (ALRU) system is a system that updates
the data bases of LMOS in response to a service order.
Work Orders can either involve a bulk task such as a large cable throw of
400 pairs from cable 102 to cable 109, which would use a special bulk-oriented
program in the Work Order process, or smaller tasks concerning a few cables,
which would use the Enter Cable Change or ECC transaction.
Below is a summary of the Service Order flow through LMOS.
1: The customer requests new or changed telephone service for their line.
2: The request is entered into the BOC's service order network to be 'worked'.
3: A request is made to assign facilities necessary to install or modify the
customer service.
4: Facilities are assigned and information is sent to the service order
network.
5: The service order network forwards information to do work to the installer,
or the RSB person who does the actual repair or modification on the line.
6: Installer completes work, returns notice to service order distribution
network that service order has been completed.
7: Completed service order goes to the BOC interface program to perform data
transactions for standard ALRU input.
8: A day's worth of service orders are accumulated and read into the ALRU.
9: Automatic Line Record Update automatically updates the LMOS host database.
Next is a summary of the Work Order flow (for BOC initialized plant changes).
1: The Distribution Service Design Center forwards requests for loop facility
additions or rearrangements to the Construction Maintenance Center to be
worked.
2: If the request for work involves existing facilities (ones that are already
there), facility assignment information is requested.
3: Facilities assigned to the Work Order are forwarded to the Construction
Maintenance Center.
4: The Construction craft (installers) receives the work instructions.
5: Work is completed and notices are sent to the CMC.
6: A paper record of the completed work order is distributed to LMOS.
When service order and work order activities are combined, an estimated
20 megabytes of data in the LMOS host data base is modified in some way every
working day.
Part II-MLT
The basics of LMOS have been covered in part I. Part II will take a
closer look at the Mechanized Loop Testing process and its relation with LMOS.
As mentioned previously, the equipment for the MLT system is located in
or near the Central Office or End Office in which the customer loops
terminate. The MLT equipment (being a third generation of automated testing
system) is connected by test trunks through the switching system to customer
loops. The MLT controller located in the Repair Service Bureau enables tests
to be made on up to 12 local loops simultaneously, sets up the testing
sequence, and controls the connection of test equipment to the loops. To make
the appropriate tests, information in the LMOS data base(s) about the customer
loop and station equipment is transmitted to the MLT controller when the test
request is initiated. This information controls certain phases of each test
and is used to analyze and decipher test results.
On command from the MLT controller, which will now be referred to as
simply 'the Controller', the MLT system dials the number to be tested. If the
line is busy, the cause is automatically determined (a conversation, phone
off-hook, or a fault), and further tests are not made until the line is free.
If the line is idle, the MLT system proceeds to make tests for purposes of
maintenance and detection of faults in the loop.
MLT test specifics