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What was that Qwest tech talkin' about?

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"LMOS ( Loop Maintenance Operations System ) - a family of integrated computer-based operations support systems that control the repair and maintenance of telephone lines. Qwest uses LMOS to initiate, track and analyze customer trouble reports on POTS ( Plain Old Telephone Service ) subscribers. LMOS is the standard repository used to reference issues regarding customer service recorded as trouble tickets."


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Is this still effective on their digital subscriber lines?


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Hell, I forgot my password. Oh well. I can tell you alot about LMOS. It's basically one of the computer systems that used to be combined with LFACS to create COSMOS in the earlier days. You still could say that COSMOS is around, because it's essential components are still widely used in testing and blah blah blah. There is a ton of information on LMOS in my copy of Engineering and Operations in the Bell System. Relevant information. I'd try and get ahold of this book if I were you, that is if you're curious about LMOS. Ah, hell I'll just transcribe. Give me a few minutes...



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I should be getting ahold of a more recent version of this pretty soon, maybe next week. When I get it, I'll transcribe that as well. LMOS is a pretty interesting system overall though. Lots of interesting functions and uses.


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. 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. 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. 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. 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.


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).


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