A Computerized Test System for Communications Equipment Subassemblies

This paper describes an automatic test system for factory testing of telephone carrier equipment channel units. The system is intended for high volume subassemblies such as those found in pulse-code-modulation carrier systems where, typically, there are 24 units in each terminal. With the greater availability of minicomputers and digitally programmable instruments, a system is feasible at moderate cost. The system described uses a low-cost self-contained eight-bit minicomputer as the test sequence controller. Control information is transmitted to and from the various instruments by way of a data input-output buffer. A reed contact switching matrix is used to interconnect commercial equipment that is used to generate inputs and measure results. The resulting system is capable of making up to 100 functional tests on a channel unit in less than one minute. Significant savings have been possible in testing time and labor cost. Also, equipment reliability is improved because of uniform testing methods.