Check to see if phone is busy.

Hi There,

I want to check if a phone (modem, ISDN) connected to my computer is available or not, so I can see if I can make a call or not.
It doesn't have to be connected to the internet, but it could also be that I am calling to another person with this device (now why would I do that? :)).

Greetz,
Bart

PS: I tried it this way, but I heard this doesn't work with ISDN:

Code:

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Public Function ModemBusy(iComPortNo As Integer) As Boolean

  Dim iFreeFile As Integer

On Error GoTo ErrorHandling

  iFreeFile = FreeFile()

  ' Open the communications port.
  Open "COM" & iComPortNo & ":" For Output As #iFreeFile
  ' Send attention (AT).
  Print #iFreeFile, "AT"
  ModemBusy = False

ExitGracefully:
On Error Resume Next

  ' Close the port.
  Close #iFreeFile

  Exit Function

ErrorHandling:
  ModemBusy = True
  Resume ExitGracefully

End Function

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