Contact Behavior of Telephone Relays and Connectors in Various Aggressive Environments

Air pollution contributes to the degradation of the reliability of telephone switching relays. To study pollution effects on the French crossbar telephone exchange system we conducted three studies: first, atmospheric analysis in some telephone central offices; second, surface analysis of contacts from telephone exchanges; and, third, laboratory simulation tests in order to accelerate the harmful effects of natural exposure. This paper reports the methods used, and gives some results on the 'behavior of connectors and relays in some aggressive atmospheres.