Metroliner telephone article 4101
writes:
A friend of mine once built IMSAI boxes to use as data concentrators, first into a Burroughs 17xx, then into the IBM System-3 that replaced it. It took a while to get the interface to the IBM machine going, because it turned out that the signal levels used by the IBM equipment didn't match the RS-232 standard. This led to a very interesting argument with the IBM people:
Answers below refer to US-CA style power; the details will be different in 240V countries I know you can transmit across the two halves of a single...
Him: Your equipment doesn't comply with the specification. IBM: Yes it does. Him: Do you claim to be RS-232 compliant? IBM: Yes. Him: Well, RS-232 states that quotes relevant specs IBM: But our specifications state that quotes incompatible specification Him: Yes, but you claim to be RS-232 compliant, and RS-232 states that more quotes, heavy on the word SHALL
Phil Kane It wasn't obviously as good as now, but people found ways to stay connected. Keep in mind the original theme of this thread--improved mobile phones on a train used by...
IBM really wanted this sale; it was going to be the first System-3 model 15D in town. They laid down plywood on the carpet in the boardroom and set the machine up there, hoping that my friend's employer would like it enough to move it into the machine room where the Burroughs box was still running. This gave my friend enough leverage that he eventually got IBM to back down, and forced them to modify their equipment so that it indeed complied with RS-232.
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At radio frequencies, which is what we are talking about here, the signal travels on the surface of the wire and doesn't penetrate the metal to any depth. Thickness...
Metroliner telephone article 4102
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