Assign the fileref for a graphics stream file and set the graphics environment. Set graphics stream file characteristics, and select CGMCRT device drive for binary CGM. 
filename gsasfile 'external-file';
goptions reset=global gunit=pct border cback=white
         colors=(black)
         gaccess=gsasfile gsfmode=replace
         noprompt device=cgmcrt
         hsize=5 in vsize=5 in;