The Field Test Display is located at the end of the main menu loop. It can be activated (or deactivated) in the following ways:
The field test data will then appear in a moment. The index of the test will appear on the top right corner of the display.
Or, alternatively:
When the Field Test Display is active, the phone works mainly in a similar way as without it, except that the arrow buttons (up, down) scroll through the various tests, whereas they would scroll through the short code memory while the Field Test Display is inactive. There may also be some other differences compared to the operation of normal NSE-3/NSK-3 terminal.
The Field Test Display appears as a so called soft indicator, which means that it is visible only if there is nothing else to display. For example, once the first digit of the phone number has been dialed, the Feild Test Display disappears and the digit appears. After the whole number has been dialed, the number dissapears and the Field Test Display reverts.
The only way to deactivate the Field Test Display is to enter a zero to the TEST prompt in the NET MONITOR menu and confirm it with the OK button.