TS-450S/690S1. Press and hold in the [ENT] key and turn the power on.
2. Turn the M.CH/VFO CH control to select menu number 01 on the display.
3. Press the UP or DOWN key to turn the display on.
4. Press the CLR key.
5. If the installation location is changed or the AT-300 is removed, select OFF in step 3 above.