Hi Frank,
As far as I am aware the HS series uses HPGL language. It is similar to Gcode but it does not contain the Z axis position data (other than pen up / pen down). There are some programs available that will convert HPGL to Gcode so it is quite possible that a conversion between Gcode and HPGL could easily be made but, as far as I am aware, there is no way to incorporate any Z axis linear positional data.
Hope this helps.
Tweakie.