Tapi und Excel

Private Declare Function tapiRequestMakeCall& Lib "TAPI32.DLL" _  
(ByVal DestAddress$, ByVal AppName$, ByVal CalledParty$, ByVal Comment$)
' Possible error return values from tapiRequestMakeCall function  
Private Const TAPIERR_NOREQUESTRECIPIENT = -2&
Private Const TAPIERR_REQUESTQUEUEFULL = -3&
Private Const TAPIERR_INVALDESTADDRESS = -4&
Private Const TAPIERR_INVALPOINTER = -18&
 
Sub Dial(strPhoneNo As String, Optional strCalledParty As String, _
Optional strComment As String, Optional bError As Boolean)
Dim strErr      As String
Dim lngResult   As Long
Dim strCaption     As String
 
    ' Assign Default values to optional arguments  
    If IsMissing(strCalledParty) Then strCalledParty = ""  
    If IsMissing(strComment) Then strComment = ""  
    If IsMissing(bError) Then bError = True
 
    lngResult = tapiRequestMakeCall&(Trim(strPhoneNo), strCaption, strCalledParty, strComment)
    'Display error message unless requested otherwise  
    If bError And lngResult <> 0 Then
        strErr = "Error dialing " + strPhoneNo + ": "  
        Select Case lngResult
            Case TAPIERR_NOREQUESTRECIPIENT
                strErr = strErr & "Unable to start/use Dialing application."  
            Case TAPIERR_REQUESTQUEUEFULL
                strErr = strErr & "Dialing requests queue is full."  
            Case TAPIERR_INVALDESTADDRESS
                strErr = strErr & "Phone number is invalid."  
            Case TAPIERR_INVALPOINTER
                strErr = strErr & "Pointer error."  
                ' This error should not occur  
            Case Else
                strErr = strErr & "Unknown error."  
                ' The four errors listed are all of the current function  
                ' error returns but who knows what the future will bring  
        End Select
        MsgBox strErr, vbOKOnly + vbExclamation, "Dialing Error"  
    End If
End Sub
 
Sub Reader()
Dim rngPhone As Range
Dim rngCell As Range
Set rngPhone = Application.Range("Phone")  
 
    For Each rngCell In rngPhone
        Dial (rngCell.Value)
    Next rngCell
End Sub