Serial Issues
Way back in the mid-eighties (so exact details may be hazy) we had issues hooking up plotters to the VAXes, coincidentally at both my first two jobs. In both cases we didn't have any spare serial lines to dedicate to the plotters so they needed to share with the associated VT terminals.
First one we managed to develop a simple splitter which seemed to work, on the second one the support for the department had managed to hook up the plotter on pass-through from the terminal but every now and then it would just stop. I was asked to take a look and tracked it down to an escape code for the terminal being sent as part of the data for the plotter. A bit of tweaking of the driver to disable the terminal during plotting fixed the problem.
Now where's my serial BoB*?
*Break Out Box
Biting the hand that feeds IT
