Access does not support serial I/O directly and you will need to use a
3rd party tool to do the job. The easiest tool to use for the type of
application that you describe is a product called WinWedge from TAL
Technologies, Inc. For more information about WinWedge visit:
http://www.taltech.com/TALtech_web/products/winwedge.html
WinWedge is an executable program that is designed to run in the
background and feed incoming serial data directly to other Windows
programs line Excel, Access, etc. by either stuffing the serial data
into the keyboard buffer so that the data appears as if it is being
typed in or the program can also pass the data using Dynamic Data
Exchange (DDE). With the DDE method, you can set up WinWedge to
trigger an event in Access so that it runs a VBA subroutine when
serial data is received and the subroutine can then perform a DDE
request back to WinWedge to get the serial data and put it wherever
you want the data to go (into a textbox, directly to a table, etc.)
WinWedge also supports full two way I/O so you can send data out the
serial port as well. It is a very easy program to use and should have
you up and running in short order.