Its fairly trivial to write a small .net console application that just stores serial port data to a file. Here is roughly what it would look like in Visual Basic.net. Obviously a complete program would include error handling and possibly command line options.
'Open a log file for writing
Dim f As System.IO.FileStream
f = IO.File.OpenWrite("C:\SERIAL_LOG.bin")
'Open a serial port at 3Mbps
Dim p As IO.Ports.SerialPort
p = My.Computer.Ports.OpenSerialPort("COM1", 3000000, IO.Ports.Parity.None)
'Keep writing serial data to the file until the user presses the ESC key.
While Not (Console.KeyAvailable AndAlso Console.ReadKey().Key = ConsoleKey.Escape)
If p.BytesToRead > 0 Then
'closer serial port
If p IsNot Nothing Then p.Close()
'close log file
If f IsNot Nothing Then f.Close()
You can get one of the free versions of visual studio here.
You can fine the official documentation for all thing visual studio at
After you are done capturing, you can then view the raw data in a hex editor/viewer such as HxD.