In Reply to: RE: Couple more premium CAT-7 posted by unclestu on July 29, 2015 at 23:35:28:
The first Ethernet controller that DEC sold worked on the fat (RG-8U compatible Triax). The controller included a built in Time Domain Reflectometer that could give an approximate location of a cable fault.
One of the early customers for these devices was Sandia National Laboratory. They put some of their test equipment into a hole in the ground together with a PDP-11 minicomputer that had the Ethernet adapter. The instrumentation was intended to measure the performance of an underground nuke. Here the high speed (10 Mbps in the early 80's) allowed more data to be sent before the computer and related equipment ceased to exist. (This was a source of ongoing computer business for us.)
The people from Sandia liked the TDR capability of the Ethernet controller that was in another PDP-11 safely above ground. After communication with the underground system was gone they ran the TDR and got the length of the remaining coax. This provided a quick and dirty indication of the success of the blast. :-)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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Follow Ups
- Another application for TDR :-) - Tony Lauck 07/30/1508:10:10 07/30/15 (0)