Navtel 9460 Protocol Analyzer info?

One use of a protocol analyzer. In one of my previous lives I worked for AT&T Western Electric. I arrived just as Ma Bell and the Babies were splitting, around 1983-1984. We used a protocol analyzer all the time when troubleshooting our Gerber photo plotter. The Gerber plotter used a series of collimated apertures to generate lines in the photoresist of master circuit masks. We were making masks for circuits and the plotter would have issues with some of the plots we generated. The Plotter ran in a dark room over a granite table to make the master mask. One problem was that occasionally on very long lines the plotter had timing issues. We found that plotting several shorter lines worked better. Also we had problems when drawing "circles" which were actually many sided polygons. We used a HP protocol analyzer and found that we could create and try different sets of test cases very rapidly. We would also store up the entire set of plot commands and replay them trying different permutations. We generated the production plot commands using a "C" program on an AT&T 3B2 or on one of our PDP-11/70's. All of our production systems were dual PDP-11/70's. Each unit had its own pair of disks and a connection to a shared dual ported drive that we used as a swap drive for backups. We could tweak commands using the protocol analyzer, change plot line widths, plotter speed, and select a different aperture, and modify acceleration and deceleration rates. Kind of like playing with HPGL commands. I can't remember if I went to the week long class to learn how to operate the unit. I know that Western Electric was big on training classes. Mike