Look here and see if this helps:
http://www.linuxcnc.org/docs/2.3/htm...1,-G61.1,-G64:
Also in stepconf you can set a parallel pin for digital out, then this pin is
controlled by m62 -65 - a little bit cleaner then using coolant m code (but doesn't really matter)
Here is a link for another fancier laser controlled by EMC2:
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?M5i20_Laser
doesn't talk too much about the g coding side thou.
Chris M