PARALAN MODEL ST123

The Model ST123 has been shipping for several years. It performs a pin-to-pin continuity and shorts test and what we call an integrity test that assures that SCSI signal pairs are connected to twisted pairs in the cable. The ST123 has an LED indication of faulty pins in the continuity test and of faulty pin pairs in the integrity test. We assume that the cable assembly is made with cable that meets the SCSI specifications for impedance, shielding, twisted pairs, etc. The ST123 has connectors for testing cables with 50-pin high density and 50-pin centronics type connectors as well as the 68-pin high density. We offer an adapter for testing of cables with one or two 68-pin VHDCI connectors. Other than plugging the ST123 into a power line, there is no set up required and a SCSI cable assembly can be tested in a few seconds.

A few words about the importance of the integrity test in the testing of SCSI cables: At the speed that SCSI operates, the cable is an rf transmission line. As with all rf transmission lines the impedance of the line is very important in order to minimize the amount of energy reflected from the receiving device back to the transmitting device. These reflections can cause many very hard to trouble shoot problems ranging from a system that refuses to boot to a fault that occurs very infrequently. It is extremely important that SCSI signal pairs are assigned to twisted pairs in the cable in order to maintain the impedance that the cable is designed to meet and to reduce crosstalk to a minimum. Passing the continuity and integrity tests of Paralan SCSI Cable Testers assures that the cable assembly is not the source of problems in your SCSI system.