Hi,
Interfacing serial devices is straight forward. You can download
NETComm.ocx from my homepage, or use any one of several .NET classes that
wrap the Windows serial APIs, using P/Invoke.
I have several scale examples in my book. See below. Scales have no
standard communications protocol, so you have to write code that uses the
data furnished by the scale manufacturer. Usually, this amounts to only a
few lines of code that parse receive data.
USB devices use whatever API is provided by the manufacturer. There isn't
any USB support in .NET (USB is a bus, like PCI or ISA -- the API is defined
by the device, not the bus).
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.