Connect 7220C to modem port. No null modem cable needed. Use hp-plot.sh to convert PostScript to HPGL using GhostScript and hpgl.ps ** WARNING: coordinates may come out negative. If they do add a translate PS command after the comments in the PS file. Use cat-serial to send HPGL output to plotter. It will automatically buffer. If output is too faint slow the pen down by adding a VS command to the HPGL just after the IN; command. VS1 worked well last time with how dried the pens were.