Option Explicit
 
Private Sub Text1_KeyPress(KeyAscii As Integer)
    If Text1.SelStart = Text1.MaxLength - 1 Then
        Text1.Text = Text1.Text + Chr(KeyAscii)
        Text2.SetFocus
    End If
End Sub
 
Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKeyRight And Text1.SelStart = Text1.MaxLength Then _
      Text2.SetFocus
End Sub
 
Private Sub Text2_KeyPress(KeyAscii As Integer)
    If Text2.SelStart = Text2.MaxLength - 1 Then
        If IsNumeric(Chr(KeyAscii)) Then
            Text2.Text = Text2.Text + Chr(KeyAscii)
            Text3.SetFocus
        End If
    End If
End Sub
 
Private Sub Text2_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKeyRight And Text2.SelStart = Text2.MaxLength Then _
      Text3.SetFocus
    If KeyCode = vbKeyLeft And Text2.SelStart = 0 Then Text1.SetFocus
End Sub
 
Private Sub Text3_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKeyLeft And Text3.SelStart = 0 Then Text2.SetFocus
End Sub

NS