ce1zzes@prism.gatech.EDU (Eric Sheppard) (08/16/90)
A peculiar thing has happened to a couple of Model 50's here. The serial port has failed on the machines. I placed a monitor on a port and noticed (compared to a functional port) that three handshake lines have changed polarity. DTR, DSR, and RTS, normally positive, have inverted and become negative. The change has knocked out communications with an electronic printer switcher, which requires the handshake lines. Any ideas as to what may have happened? Eric