Private Sub Form_Load()
   Text1.MaxLength = 5
   Text2.MaxLength = 5
   Text3.MaxLength = 5
   Text4.MaxLength = 5
   Text5.MaxLength = 5
End Sub

Private Sub Text1_Change()
   If Len(Text1) = 5 Then Text2.SetFocus
End Sub

Private Sub Text2_Change()
   If Len(Text2) = 5 Then Text3.SetFocus
End Sub

Private Sub Text3_Change()
   If Len(Text3) = 5 Then Text4.SetFocus
End Sub

Private Sub Text4_Change()
   If Len(Text4) = 5 Then Text5.SetFocus
End Sub

Private Sub Form_Load()
   Txt(1).MaxLength = 5
   Txt(2).MaxLength = 5
   Txt(3).MaxLength = 5
   Txt(4).MaxLength = 5
   Txt(5).MaxLength = 5
End Sub

Private Sub Txt_Change(Index As Integer)
If Len(Txt(5).Text) = 5 Then
   'Opción de salida cuando llegue al ultimo textbox
Else
   If Len(Txt(Index)) = 5 Then Txt(Index + 1).SetFocus
End If
End Sub