Switching Systems

A Guide to Credit for Prior Learning

Typical Learning Experiences of Students Earning Lower-Level Credit:

  • Successfully complete courses in switching systems provided by their companies.
  • Complete hands-on work in switching systems for their companies. This hands-on application is in addition to the laboratory portion of the courses taken, and is typically, but not necessarily, required. Because of the nature of this particular CBE, the knowledge gained is usually theoretical AND hands-on.

Typical Learning Experiences of Students Earning Upper-Level Credit:

  • Due to the introductory nature of these items, upper-level credit is usually NOT appropriate. Special exceptions to this would be appropriate if the student has extensive hands-on work in the installation, analysis and design of switching systems installation. For example, the student may have worked with engineering to layout the installation plans, specify the wiring types and conditions, and have been the supervising installer for major installations. In this case, more specific titles for the credit may be appropriate (such as “installation management”)

Background and Historical Explanation

Over the course of time, the vendor introduced various Electronic Switching Systems (ESS) (#1, #1A, #2, #3, #4 and currently #5). With the introduction of each ESS system (technology thread) the vendor chose to develop a series of courses that trained the installers to prepare, install, test, verify operation and troubleshoot the particular system. For simplicity sake, the courses are grouped in levels (beginner, intermediate, advanced and top-gun. Depending on the expectations of the installer, the vendor chose to send the student to the various levels of courses offered.

During the lives of ESS systems ( #1 - #5) more effort was put into the design, ease of installation, and troubleshooting of the switch. For example where it took a cadre of personnel thousands of man-hours of installation for a #1 switch, the installation of a #5 ESS system takes a few weeks. Installation, operation and troubleshooting procedures became easier, as the technology threads advanced, and therefore the amount, level and complexity of training became lower for the installers and troubleshooters. The time spent in courses went down substantially, as did the generalizability and complexity of the training. Due to engineering, the ESS systems also became more “plug and play”, foolproof, easy to use, and self-diagnosing, and therefore the installers training and knowledge became simpler and less global. For example in the installation of the #1 switch, Boolean logic, AC/DC theory, digital logic and microprocessor theory were necessary. For the installation of the #5 switch, these core elements were totally hidden behind self-diagnostic software, operating systems and user shells. Although the systems themselves became more complex, and robust, the installer’s knowledge level became more focused, and less generalizable.

Some serious examination and evaluations of credit for coursework in switching systems had been done in the past by the National College Credit Recommendation Services (National CCRS), formerly known as the National Program on Noncollegiate Sponsored Instruction (National PONSI). The CCRS evaluation of Western Electric Company courses in the early 1980’s and of NYNEX training courses, laid the groundwork for credits in this area. What follows is an extension, clarification and elaboration of these into a total package.

This guide for switching systems covers only the #1, #1A and #5 ESS systems. This was done to keep the guide manageable. It should be noted that the systems noted above are the predominate systems and do encompass a vast majority of the training offered. The remainder of the systems (#2, #3, #4) are smaller in scope and impact very few students.

Duplication of Technology Threads:

It may happen that the student has taken the full technology thread for multiple switching systems. For example, the student may have taken the beginner, intermediate and advanced coursework for both the #1 and #1A system. There is extensive duplication of the theory between the #1 and # 1A systems and full credit will not be given for both tracks. If the student can show theory knowledge, as noted below, for both systems, additional credit may be given, but not at the full rate.

There is less duplication between the #1, #1A technology threads, and the #5 thread. The difference can be compared to knowing assembler language, and Windows. There is duplication in theory between the concepts of ESS systems, but the duplications stop there. If the student has taken the technology thread in both the #1 series and the # 5 series, based on the comprehension gained, credit can be awarded for both, but it is suggested that it not be additive.

Discussion Topics:

If students are familiar with some (but not necessarily all) of the following, they may be eligible for the noted credit in the area of “switching systems.” If the knowledge of some of the following topics is considerably more substantial than knowledge of others, they may consider requesting credit in a narrower area of switching.

Technology Thread: ESS #1 - Switching SystemIntroduction to Electronic Switching Systems

Level: Beginner

  • What are the processor parts?
  • What are the test commands?
  • Define the trouble locating procedures?
  • Define and explain frame identification?
  • Explain the trunk lines and the test panels.
  • Explain the initialization procedures.
  • Define the diagnostics procedures.

Central Processor Hardware, Language and Testing

Level: Intermediate

  • Flow chart the manual testing of the DACC/MACC and CC.
  • Explain the initialization and sanity program execution.
  • Define what IOMP frames are.
  • Explain how to use normal test equipment (oscilloscope, signal analyzer).
  • Define and explain Boolean logic.
  • Explain logic gates and gating.

Electronic Switching Systems Verification and Testing Theory

Level: Advanced

  • Flow chart the normal diagnostic and troubleshooting tasks necessary to make the system fully operational.
  • Explain the parts of the generic system documentation.
  • Identify how to initiate an audit test.
  • Explain what a typical diagnostic test result tells you.
  • Explain call processing parameters.
  • Explain how you get an audit error printout.
  • Flow chart how you troubleshot the entire system hardware.
  • How do you identify call processing failures?

Technology Thread: ESS #1A - Switching SystemIntroduction to Electronic Switching Systems and Peripheral Hardware

Level: Beginner

  • What are the processor parts?
  • What are the test commands?
  • Define the trouble locating procedures?
  • Define and explain frame identification?
  • Explain the trunk lines and the test panels.
  • Explain the initialization procedures.
  • Define the diagnostics procedures.

Central Processor Hardware, Language, Testing and Auxiliary Units

Level: Intermediate

  • Flow chart the manual testing of the DACC/MACC and CC.
  • Explain the initialization and sanity program execution.
  • Define what IOMP frames are.
  • Explain how to use normal test equipment (oscilloscope, signal analyzer).
  • Define and explain Boolean logic.
  • Explain logic gates and gating.

Electronic Switching Systems Verification and Testing Theory

Level: Advanced

  • Flow chart the normal diagnostic and troubleshooting tasks necessary to make the system fully operational.
  • Explain the parts of the generic system documentation.
  • Identify how to initiate an audit test.
  • Explain what a typical diagnostic test result tells you.
  • Explain call processing parameters.
  • Explain how you get an audit error printout.
  • Flow chart how you troubleshoot the entire system hardware.
  • How do you identify call processing failures?

Electronic System Verification and Operation

Level: Top-Gun

  • Detail how a call processing failure occurs, and how to remedy it.
  • Explain how an audit printout defines failure location and identification.
  • From a diagnostic test results printout, detail the next possible steps.
  • When a maintenance interrupt printout occurs, explain the next possible steps.
  • Explain how a call processing translation trouble could occur.
  • How could call processing translation troubles be resolved?
  • Graphically define the normal subsystems of a #1A ESS system.

Technology Thread: ESS #5 - Switching SystemSwitch Equipment Installation and Verification

Level: Beginner

  • Define the preliminary installation procedures.
  • Explain all the necessary physical hardware and their functional descriptions.
  • Explain equipment erection procedures.
  • Define the necessary steps for cabling operations.
  • How do you perform a power verification procedure?
  • Explain the wire continuity test procedure.
  • Explain the system MCC page.
  • Explain how the MCC page tracks troubles.

Hands-on Electronic Switch Installation

Level: Intermediate

  • Define how to isolate faults and define the resolution.
  • Explain initialization and recovery procedures.
  • What are the operational procedures for the switch?
  • How do you determine what recent changes took place?
  • How do you do line and trunk testing?

Switch Installation System Testing

Level: Advanced

  • Explain the RT and OSDS system environments.
  • Outline the parts and function of the switch database.
  • Explain how to use the office database editor.
  • Explain how to do fault analysis on a switch.

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