// Loop Maintenance Operations System (LMOS)
//
// by Brisk Attivo
//
// http://www.oldskoolphreak.com

16.3.2. LOOP MAINTENANCE OPERATIONS SYSTEM (LMOS)

When a clerk takes a report in a repair service bureau 
that uses only manual methods, a trouble ticket is filled 
out. This ticket includes the customer's name, address, 
telephone number, and any pertinent information that may 
help to identify the trouble. All of this information is 
entered on the ticket manually, with the ticket eventually 
passing through many hands. In addition to this source of 
information, cable pair assignment, cable makeup 
information, and trouble history for each customer are 
kept on file in large bins or file tubs. This information 
is used by the tester to help isolate the problem. Through 
the use of LMOS, all of this information can be stored in 
a computer and displayed on CRTs at the 611 position and 
other locations. In addition to simplifying information 
retrieval, the accuracy and readability of the information 
will be greatly imporved. The CRT display will alow the 
RSB to advice the customer immediately of the status of 
the trouble, should the customer happen to make a followup 
inquiry. It also produces administrative reports including 
jeopardy reports, facility status reports, cable fill 
reports, and reports with respect to closed out troubles. 
LMOS includes documentation such as training materials and 
position practices.
LMOS can be installed separately or with the LSV or 
mechanized loop testing (MLT) modules, which mechanize 
important testing functions. The system economically 
viable for typical groupings of repair service bureaus 
that serve on-half million to five million lines.
Labor savings benefits result from:

(1) Mechanization of the line record.

(2) A mechanized service order inteface for automatic line 
record updating.

(3) The ability to centralize the repair service 
attendants for many repair service bureaus.

(4) A flexible report generator that produces standard 
statistics or processed trouble reports and special 
reports on demand.

(5) A repair force administration algorithm that optimizes 
the travel time of the repair personell.

LMOS is a 3-level network interconnected by data links as 
shown in Fig. 16-2. The hub of the network is an IBM 370 
computer and associated peripherals. The master line 
record data base is maintained in the hub, which can 
support up to five million working lines.

Fig. 16-2. Loop Maintenance Operations System

The second level of the system consists of a number of 
satellite locations which are linked with the central data 
base. A satellite consists of a PDP 11/70 minicomputer and 
associated peripheral equipment. Each satellite has an 
estimated capacity of one million lines. The satellites 
support almost all of the real-time transactions and 
provide response times on the order of 5 seconds or less 
for most transactions. Because these satellites have such 
a large capacity and since the cost of the minicomputer 
equipment is a minor portion of the overall system cost, a 
duplexed configuration is reccomended for reliability.
The third level of the system is at the repair service 
bureaus and centralized repair service attendant 
locations. Each location has a PDP 11/10 minicomputer 
which is linked with one of the satellite minicomputers. 
The repair service attenants and other personel interact 
with the system through CRT terminals, printers, and 
status entry devices which are special purpose data entry 
terminals that enter data with a TOUCH-TONE pad and 
display data on a light-emitting diode readout strip.
The lower limit on the capacity of a LMOS installation is 
based on economic constraints imposed by fixed cost items 
such as software support personnel, training center costs, 
and IBM 370 costs. This limit is estimated to be 500,000 
lines.

16.3.2.2 Operations

The following descriptions of ways that LMOS can be used 
in an operating company will further explain the 
organization and functions of the system.

The Repair Service Attendant Position.

Each repair service attendant position is equipped with a 
CRT terminal through with LMOS accepts trouble reports. 
Following keyboard entry of a customer telephone number or 
special service circuit number, LMOS responds with 5 
second with a CRT display that includes:

(1) Customer name, address, and service data such as 
disconnected, non-working, affiliated with a telephone 
answering service, or date of last trouble.

(2) An appointment time that can be offered to the 
customer if a repair visit appears to be neccessary.

(3) LSV or mechanized line testing system responses ( if 
installed at serving RSB) to LMOS initiations.

(4) Information on cable and other equipment failures that 
are known to be affecting the particular customer's 
circuit.

(5) Information on the initial report (if the current 
report is identified as a subsequent report) concering 
repair status, promised appointment time, and number of 
previous subsequent reports.

The appointment time mentioned above takes into account 
both of the back-log of trouble reports awaiting dispatch 
and the size of the craft force responsible for the 
corresponding repair coverage.
The LSV or mechanized line testing system response usually 
is not available at the time of the initial trouble report 
transmission, but is writen into a reserved space on the 
display as the repair service attendant is talking to the 
customer. REsponse time of these systems is on the order 
of 10 seconds and can be longer if delays are encountered 
because of test equipment usage.

As in the case of the appointment time offering, the LSV 
or mechanized line testing system response is made from 
the RSB covering the service in question and need not be 
the same RSB that contains the originating repair service 
attendant position. It is the independence of the repair 
service attendant from the responsible RSB that permits 
one of the more significant operational capabilities: 
centralization of the repair service attendant task. Such 
centralization is possible because all of the repair 
service attendant transactions are designed to operate 
with acces to all of the line records contained within the 
serving satellite minicomputer (this also implies acess to 
all LSV and mechanized line testing systems covering these 
lines). Thus, 24-hour coverage and other desirable 
features possible with a centralized repair service 
attendant location are provided within the LMOS design.

16.3.2.3 RSB Handling of the Trouble REports

Once a trouble report has been entered in LMOS, the line 
record data base is accessed and a basic output report is 
transmitted within seconds to a printer at the appropriate 
RSB. In addition to the trouble report and line record 
data, this paper document contains:

(1) Assignment information.
)2) Service and equipment information.
(3) Trouble history for the past 40 days.
(4) Warning of potential trouble causes such as cable 
failures.

As repair action takes place following a trouble reports, 
status updates, such as test results and trouble reports 
closeouts, are entered into LMOS in the RSB, using status 
entry devices described previously.
LMOS will aid in the dispatching of the repair force 
through the use of a repair force administration module 
that will provide a CRT-equipped dispatcher with a short 
list of reccomended dispatches each time a member of the 
repair force calls in for a new dispatch. Repair force 
administration will take into account the repair work 
backlog, available repair force, promised appointment 
times, and travel times.
Note that since ach line record is keyed to a serving RSB, 
LMOS permits functional repair operations such as coin 
telephone repair centers and PBX repair centers; the basic 
output report always arrives at the correct serving RSB or 
repair center.

16.3.2.4 Control of Testing

Not only can the repair service attendant position trigger 
LSV action against a particular telephone number, but also 
RSB personnel can use LMOS to drive a LSV in an automatic 
verification mode. This is done by using a RSB CRT 
terminal to enter a list of telephone number, a particular 
cable complement, a range of central office equipments, or 
a specifc class and period of closed-out trouble reports 
such as all-test-OKs for the last two days. LMOS then 
acceses its data base for cross-reference lists that 
provide the appropriate telephone numbers and initiates 
automatic sequential line status verification against the 
telephone number list. Results are printed out at the 
requesting RSB within seconds of completion. The testing 
capabilities of the mechanized line testing system can be 
used by LMOS in the same manner.

16.3.2.5 Operational REports

Over and above individual trouble report tracking, LMOS 
provides three basic classees of operational reports: one 
covering open troubles, one covering closed-out reports, 
and one covering the line record and equipment file.
Open trouble reports are used to aid in the hour-to-hour 
administration of the RSB. An example of this kind of 
reportis the jeopardy report, which flags trouble reports 
in jeopardy of missing their appointment times.
Closed-out trouble reports relate to troubles that have 
been closed out within the last 40 days.
Line record and equipment reports fall into three 
categories:

(1) Batch reports that use the line record file as input, 
for example: all circuits on temporary suspension can be 
listed by telephone number.

(2) Batch reports that list unallowed multiple assignments 
of cable and pair or central office equipment.

(3) Equipment reports that are fixed in format but that 
are available inr elat time in response to CRT-entered 
transactions, for example :cable pair versus telephoen 
number by complement.

Since many of these reports can be retrieved from a 
centralized location, the potential for a formal program 
of centralized analysis exists under LMOS. Note that some 
reports will be useful in connection with with operating 
company activities other than maintenance such as business 
office and network administration activities.

16.3.3. AUTOMATED REPAIR SERVICE BUREAU (ARSB)

Both LSV and LMOS initially were designed as stand-alone 
systems, LSV as a manually operated line verification 
system and LMOS as a mechanized line record and trouble 
administration system. Recently, and interface was 
provided for LSV so that it can be directed from a LMOS 
operator's position to run its sequence of measurements on 
a particular line. This is a first step toward a total RSB 
system concept.
Developpment is under way for a mechanized line testing 
(MLT) system, which is an improved version of the LSV. In 
addition to improved testing capabilities, it will have 
the ability to test in the presence of known terminations. 
In the new arrangement, the MLT system, working in 
conjunction with LMOS, will have a priori knowledge of 
expected values and allowable deviations for aparticular 
line being tested. For example, when testing a ground 
start PBX line, it would know that -48 volts is the normal 
on-hook condition, whereas this would indicate a fault for 
a station line. The new system also will make routine 
rapid scan measurements automatically during the early 
morning hours when lines are normally idle. All of these 
developments are part of what will be known as the 
automated repair service bureau (ARSB).