Indicates Software Version/Display Test Mode
Power radio off (if it's On)
Press and HOLD the "AR" button while you power up the radio.
This puts the radio in the "Test Mode". Keep pushing the "AR" button.
It will cycle through different patterns on the LCD display. At the end,
it will display One Letter and Three Numbers. A102/A104 and A105 seem to be
the current versions ??? If you sailed by it, just keep pressing the "AR"
To exit from this "Test Mode" just power down the Radio.