Number used in the Open statement to open a file. Use file numbers in the range 1-255, inclusive, for files not accessible to other applications. Use file numbers in the range 256-511 for files accessible from other applications.
Excel Glossary
Number used in the Open statement to open a file. Use file numbers in the range 1-255, inclusive, for files not accessible to other applications. Use file numbers in the range 256-511 for files accessible from other applications.