ngse18@castle.ed.ac.uk (J R Evans) (02/16/91)
A few weeks ago, I posted a request for information from a colleague who had had problems with Atari ST's being used as a terminal connected to a Camtec JNT X.25 PAD; the line drivers at both ends of the circuit had blown several times, and our comms people had suggested that the problem lay in the Atari. We received several suggestions, many pointing out that it was rather hard to believe that the Atari could generate a significant overvoltage when it contains only 5V and 12V supplies (in fact the Atari concerned was fitted with an external PSU). Several respondents suggested the possibility of a lightning induced pulse, but there was no such association with any of the instances of failure. One respondent did suggest that the earthing arrangements on the ST were less satisfactory than some other micros. In short, no-one was able to offer a reasoned explanation why either of these devices should be blamed for the failure, or substantiate the suggestion of our comms group that the Atari contained a well known defect in this area. The comms folks have now backed off their position of wishing to ban Atari ST's from connecting to the JNT X.25 PADs, and have provided my colleague with surge protectors fitted to both ends of the circuit between his Atari and their PAD. It appears to have been implicitly accepted by all that there must be something about the wiring of this particular circuit which produces (presumably inductively induced) surges from time to time. Our thanks to all who responded. Russ Evans British Geological Survey, Edinburgh e_gs18@va.nmh.ac.uk