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Current issue : #9 | Release date : 1986-12-01 | Editor : Taran King
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Loop Maintenance Operations SystemDoom Prophet & Phantom Phreaker
Phrack World News VIIIKnight Lightning
Title : Loop Maintenance Operations System
Author : Doom Prophet & Phantom Phreaker
                               ==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

     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

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

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

* AC and DC (Alternating Current and Direct Current) measurements to determine
if the loop is proper for the customer's station equipment, to determine the
type and the extent of any electrical leakage through cable insulation, and to
detect broken cable pairs and the location of the break in terms of distance
from the CO where MLT is being used.

* A 'Soak Test' to see if leakage will disappear after a high voltage is
applied from the Central Office battery. The voltage dries up moisture, which
is a frequent cause of leakage.

* A Balance Check to reveal how susceptible the loop is to noise causing
voltage, which would impair conversation over the line.

* A measurement to tell whether CO battery voltage (voltage drops when the
phone goes to an off-hook condition) and dial tone can be placed on the loop.

     All MLT test measurements are converted by the MLT hardware to digital
form and returned to the Controller for analysis. The analysis is based on the
test results and the line-record info from LMOS.

     Here is an example of how the Automated Repair Service Bureau (ARSB)
works with the repair service attendants. A customer can't get a dial tone, so
he calls the repair service from a neighbor's phone. An attendant who answers
the call types the customer's phone number into a computer terminal. In
response to this, LMOS displays the customer's name, address, class of service
(in this case, it would be residential service), and information about any
recent trouble on that loop. At the same time, LMOS causes the MLT system to
test the loop. The CRSAB Attendant types in a description of the reported
trouble. The MLT system returns the results of the tests on the line within a
few seconds. Say, for example, the fault in question was a cable fault. This
information would be displayed on the screen. The attendant would tell the
customer that a visit is not needed, and that line will be repaired by a
certain time. The data on the screen is automatically added to the LMOS
database. A BOR is printed in the RSB serving the customer, and is screened to
decide if it should be given to a dispatcher or a tester. The content of a BOR
is explained in part one, and a diagram of a BOR is included below.

**** BASIC OUTPUT REPORT *****                     PAGE- 01
UNIT-99900000  10-08-86  0300P  TTN-0000110
TN-999  5557009                                           CAT-CD
SC-1FR    CS-RES     PUB     CPE-NO    SWC-         WKNG -0-

--RCH--                                       REACH NBR-
COMM-10-09-86  0700P VER-4   CALLED NBR-        OVER-
                         STATUS-PS  10-09-77  0400P
SO DATE 03-27-85  SO# N0901

QTY-0001    USOC-1FRBC  KS-0000   LTD-   REF-
OE-000B-010-09  VT-0146  RT-0500   NSTA-0001   BRG-N   NSV-N
WC-999 F1   NPA-999    CA-   TT101    PR-109    PRU-    BP-10

NO       REPORT SUBS         CLEARED       TH-KEY  TST  RPM  O/S } T } D } C }
1  10-01-85  205P 0 10-02-77 0130P 10-02-77 620P   110  111   *  }330}320}320}



  39,200 FT (FROM C.O.)

CONTL-01 LTF-01 PORT-09 TRUNK-123 EQU-TPK000 BYD007 DLR002

     This BOR tells that the trouble is an open tip wire 39,200 feet from the
Central Office.

     The first part of the BOR up to the --RMKR-- is the basic information
section. The second part, from --TRBL-- to SO DATE is the trouble section. The
next part, from --S/E-- to TEA-R1304 is the assignment section. The fourth
part, from --HIST-- up to REPLACED INSIDE WIRE is the Abbreviated Trouble
History section. The last part is the MLT test results section.

     When a repair looks as if it may not be completed according to schedule,
a Jeopardy Report is filed. Then, more repairmen are assigned to insure the
line is repaired on time. After the repair is complete, the dispatcher retests
the loop using MLT to verify that the trouble has been dealt with. The
customer is notified, and the final disposition of trouble is entered into the
LMOS database, where it is stored for future use and evaluation. (See also
part I.)

     If you had to sum up LMOS, it would be best summed up by saying LMOS is
'A customer repair data management system.'

Misc footnotes
Section one: Acronyms

ALRU-Automatic Line Record Update
AN-Associated Number
ARSB-Automated Repair Service Bureau
ATH-Abbreviated Trouble History
BOC-Bell Operating Company
BOR-Basic Output Report
COE-Central Office Equipment
CMC-Construction Maintenance Center
CRSAB-Centralized Repair Service Answering Bureau
DDD-Direct Distance Dialing
ECC-Enter Cable Change
LMOS-Loop Maintenance Operations System
MLT-Mechanized Loop Testing
POTS-Plain Old Telephone Service
RSB-Repair Service Bureau
SS-Special Service
TAS-Telephone Answering Service
TH-Trouble History
TREAT-Trouble Report Evaluation and Analysis Tool

Section two: Automated Testing Systems

     MLT is the third generation of Automated Testing Systems. The first
generation of testing equipment was something called the Line Status Verifier,
which was manually operated, and not nearly as efficient as MLT or the second
generation, the Automatic Line Verifier. The first and second generations of
automated testing systems were both eventually built up to the MLT third
generation type of system.

-End of file-

                       References and Acknowledgements
'Automation improves testing and repair of customer loops' - Bell Labs Record
'Automated Repair Service Bureau' - Bell System Technical Journal

 And thanks to the following people for supplying other information:
The Videosmith, The Marauder, Lock Lifter, Mark Tabas, and anyone else that we
might have missed.

 Sysops are allowed to use this file as long as nothing is changed. This file
was written in 80 columns, upper and lower case.

  If you notice any errors in this file please contact one of us and changes
will be in order.
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