Chapter 20:  Acceptance Testing

Many systems and products include complete documentation, covering acceptance testing. Individual circuit packs may have their own segmented "card-level" tests, but after everything is hooked up end-to-end, a real-world test must be made to verify that the entire system is fully ready to support live traffic. For many T1 transmission systems, the bit error rate tests use QRSS (Quasi Random Signal Sequence pattern). There may be a different test strategy for each different type of T1 product, but a few common strategies are suggested in the following figure, Figure 11. The exact error-free performance requirements vary from one location to another, but if there are no other guidelines to use, start with BER of 10^-8 or better if the live traffic contains only voice channels. If data channels are present, try to start with BER of 10^-10 or better. Over some facilities, still better performance can be measured, but it takes a tremendous amount of time. For normal telco transmission facilities, acceptance tests are commonly run for periods of a few hours at most. It is most important to record all information regarding the acceptance tests. It is good form to include a copy of the product practice that lists the test procedure along with the actual results and a sketch of how the tests were run. Acceptance tests should be kept on file in every central office or equipment room.