A Field Study of the Electrical Performance of Separable Connectors

A three-year study of separable electronic connectors in operating telephone equipment was conducted to determine failure mechanisms and rates of presently used designs. The study of nine different connector types (six of which are reported) was carried out in four cities, and higher than expected contact resistances were observed. These were due to factory contaimination and not pore corrosion as originally assumed. Nevertheless, there is some evidence to suggest that a time-dependent "wear-out" mechanism exists. Finally, disengagement/reengagement cycling does not offer an adequate "fix" for reducing high-contact resistance because the frequency of reducing contact resistance is about the same as the frequency of increasing contact resistance in some connector designs. The results are from the efforts of many people working as a team at four Bell Laboratories locations and are presented in order to bring together several important conclusions.