PRN (file format)
From GICLWiki
Extension: .prn
System: AutoCAD ADI
Description: Graphic file
Extension: PRN
Program and/or Extension Function: DataCAD Windows Printer File
Company: DATACAD LLC
Specific Notes: Architectural CAD program.
File Classification: CAD/CAM
Identifying Characters: (None or Unknown)
Program ID: (None or Unknown)
General Notes: (None)