Radio Code Entry

For this example, we assume the code is 1234

Press button 1 once so that the digit 1 is displayed.
Press button 2 twice so that the digit 2 is displayed.
Press button 3 three times so that the digit 3 is displayed.
Press button 4 four times so that the digit 4 is displayed.

Once the code has been correctly selected on the radio's display, press button 5 to enter.
(in some cases, this may not work, in which case pressing 6 should work instead).