Data output file created by Printed Circuit Board (PCB) CAD tools like Altium Designer and used by PCB manufacturing machines to designate electrical connections; contains RS-274X formatted data for multiple layer boards about the layout for top copper layers; similar to the .GBL file extension.

Gerber format files, like GTL, function similar to .PDF files where they specify how a PCB should appear but are not meant to be edited. The name of the GTL file is derived from the name of your PCB. Therefore, if your PCB is called "MyProject," the file will be called MyProject.gtl. NOTE: The GTL format was originally developed by Gerber Systems but is now maintained by Ucamco.