Once in a blue moon, a nice piece of software comes your way that makes your
life a lot easier. Today was my lucky day:

http://www.serial-port-monitor.com/index.html

This "Free Serial Port Monitor" (FSPM) is a really nice (and did I say
free?) way to monitor a serial port without "consuming" the COM port.

You attach FSPM to the serial port *before* using the application that
controls the instrument (e.g., EcoView, WetView, SeaSave, etc.). It does
*not* actually "consume" the port, i.e., your instrument software will be
able connect to the COM port as usual.

For example, I am controlling my radiometers from MATLAB code. After I
start a new monitoring session in FSPM, I then open the port and communicate
with it in MATLAB as usual: [s =
serial('COM12','BAUD',9600),fopen(s),fwrite(s,...), etc.]. All the read and
write data (fread, fwrite) show up in separate panes in the FSPM
application.

The free version of FSPM lets you monitor one serial port. Pay money ($80)
and you can monitor more than one port at a time.

/eric rehm
University of Washington
Applied Physics Lab
206.354.3459