Gerber RS274

The Gerber format was originally used for the control of photo plotters. Such systems had a light source with a shutter over a so called aperture wheel, a disk with different openings in form and size. While moving the plotter table the shutter was open or closed, the light through the aperture wheel opening exposed the film.Today the photo plotters are replaced by laser plotters.

According to this kind of usage the Gerber format is a list of coordinates together with the information for the shutter mode and the position on the aperture wheel, the d-codes. There is no description for the form or size of the openings in the aperture wheel. Therefore a separate aperture file is needed, where the openings are described (see example).

Example for an aperture file	Example for a Gerber file
D11 round 4	G54D10*
D12 round 8	X0000Y0000D01*
D13 square 4	X0000Y1000D02*
D14 square 8	X1000Y1000D02*
	X0000Y1000D02*
	X0000Y0000D02*

Datatype	Description
Design layers	one file per layer
Contour	different files for the single PCB and the delivery panel if there is one format it should be gerber
Drill data	different files for PTH/NPTH/sequential PTH drill diameter defined in the file header format should be Excellon or Sieb&Meyer
Aperture description	please add the aperture file to the data set
Compression	all data specified above should be compressed in a ZIP File. It’ s helpful if the Zip file name corresponds to the project name.