Tell me how to read serial port!

dys,
You have to use a MSCOMM control (or MSCOMM AcriveX control), the following will answer your question:
The following simple example shows basic serial communications using a modem:

Private Sub Form_Load ()
      ' Buffer to hold input string
      Dim Instring As String
      ' Use COM1.
      MSComm1.CommPort = 1
      ' 9600 baud, no parity, 8 data, and 1 stop bit.
      MSComm1.Settings = "9600,N,8,1"
      ' Tell the control to read entire buffer when Input
      ' is used.
      MSComm1.InputLen = 0
      ' Open the port.
      MSComm1.PortOpen = True
      ' Send the attention command to the modem.
      MSComm1.Output = "AT" + Chr$(13)
      ' Wait for data to come back to the serial port.

Do
            DoEvents
      Loop Until MSComm1.InBufferCount >= 2
      ' Read the "OK" response data in the serial port.
      Instring = MSComm1.Input
      ' Close the serial port.
      MSComm1.PortOpen = False
End Sub

Note   The MSComm control can use polling or an event-driven method to retrieve data from the port. This simple example uses the polling method. For an example of the event-driven method, see help for the OnComm event.

This is how to read data from a serial port.

You can also check the VB help under "MSComm Control"

Best of luck.

On more thing I forgot to mention
Do not forget that you have to insert a MSComm Control from VB Prefrences (position your mouth over the toolbox and click on the right hand button of the mouse, from the pull down menu click on "Components" , find and tick "Microsoft Comm Control").
Then insert an Comm control on your form.
Have fun

dys
The above example works for sure, because I simply tried it myself

I think he is looking for a way to peek at a connection that is already open.