This works for Microstation. Notice that Microstation is called "ustn". You'll need Windows' internal name for Autocadd but this demonstrates the link:
Sub Export2Microstation()
Dim channel As Long
With Selection
FRow = .Row
RowCt = .Rows.Count
LRow = FRow + RowCt - 1
FCol = .Column
ColCt = .Columns.Count
LCol = FCol + ColCt - 1
End With
task = "PLACE LINE" 'command entry in Microstation
'replace as needed
' keyin is a command to Microstation to use the command entry box.
channel = Application.DDEInitiate("ustn", "keyin"
Application.DDEExecute channel, task
For z = FRow To LRow
Range(Cells(z, FCol), Cells(z, FCol + 1)).Select
If Len(Cells(z, FCol)) = 0 Then
Application.DDEExecute channel, tast
Else
Application.DDEExecute channel, "XY= " & Cells(z, FCol) _
& "," & Cells(z, FCol + 1)
End If
Next
Application.DDETerminate channel
Range(Cells(FRow, FCol), Cells(LRow, FCol + 1)).Select
End Sub