Hi,
You normally use whatever API is provided by the USB device manufacturer.
For example, a USB serial port or modem will use standard Windows serial
communications APIs.
However, if you have a special, purpose-built, USB device, you can use USB
APIs. These are described in detail (with examples) in Jan Axelson's book,
USB Complete 2nd Edition. I have a link to it from Books on my homepage.
Dick
--
Richard Grier (Microsoft Visual Basic MVP)
See
www.hardandsoftware.net for contact information.
Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
Edition ISBN 1-890422-27-4 (391 pages) published February 2002.