On Fri, 28 Nov 2008 08:07:01 -0800, PanuDon
wrote:

How can i use System.IO.Ports in excel 2007?
Thank you

You'd need to use VSTO (Visual Studio Tools For Office) SE to create a
NET-enabled workbook or add-in, and from there you'd be able to use
the NET BCL. You can't use NET directly within an Excel workbook.

Cordially,
Chip Pearson
Microsoft MVP
Excel Product Group
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)