5287534 "Correcting Crossover Distortion Produced When Analog Signal Thresholds Are
Used To Remove Noise From Signal"
It describes the DEC CXM04 board for the DS550 communications server, which inserts itself
between an IBM establishment
controller and a control unit (coax) terminal so the CUT can pretend it's a serial
terminal to VAXen without dropping
the polled connection to the IBM mainframe.
weird..