声明：

Private Declare Function tapiRequestMakeCall Lib "TAPI32.DLL"　(ByVal DestAddr$, ByVal AppName As String,　ByVal CalledParty As String, ByVal Comment As String) As Long
例子：
Public Sub CallPhone(Number As String, Name As String)
　 Dim lRes As Long
　 If (Trim(Number) = "") Then
　　 Exit Sub
　 End If
　 If (MsgBox("About to call " & Trim(Name)　& " at phone number " & Trim(Number) & vbCrLf & "Do it?",　vbYesNo, App.Title) = vbYes) Then
　　 lRes = tapiRequestMakeCall(Trim(Number), App.Title, Trim(Name), "")
　　 Debug.Print Now; " CallPhone -> tapiRequestMakeCall Result code = "; lRes
　 End If
End Sub

还有一种方法是：
PhoneNumber$ = "(123)456-7890"
Open "COM2:" For Output As #1 'or COM1
Print #1, "ATDT" & PhoneNumber$ & Chr$(13)
Close #1
当然，该方法只适合小型的应用。