Gerber RS247X as accepted signal file?

Hi all !
Carbide Copper is looking for a Gerber RS247X signal file. Am I dyslexic?.. I could not find any references regarding this particular version of Gerber. I’m using Eagle CAD 6.5.0 and no reference of such version exists in the CAM device output box. RS274X seems to be the norm. Can somebody kindly educate me on this situation? I’m new to this.

It’s a typo in Carbide Copper’s doc. Definitely GERBER_RS274X. I used that to export files from EAGLE (8.3.2) with Carbide’s CAM processor (here) and used that in Carbide Copper and it went fine, with two road bumps: one minor about hole scaling that required tuning the export a bit, and one major which is that the generated G-code does not raise the tool at the beginning of the job, which can easily be fixed manually in the G-code file: see Carbide Copper drill/holes scaling issue