HEIDENHAIN iTNC 530 User Manual page 109

File names
When you store programs, tables and texts as files, the TNC adds an
extension to the file name, separated by a point. This extension
indicates the file type.
PROG20 .H
File name File type
File names should not exceed 25 characters, otherwise the TNC
cannot display the entire file name.
File names on the TNC must comply with this standard: The Open
Group Base Specifications Issue 6 IEEE Std 1003.1, 2004 Edition
(Posix-Standard). Accordingly, the file names may include the
characters below:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i
j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9 . _ -
You should not use any other characters in file names in order to
prevent any file transfer problems.
The maximum limit for the path and file name together is
82 characters (see "Paths" on page 111).
HEIDENHAIN iTNC 530 109