Depending on the function mapped onto the key, the red or green LEDs on the key will be activated when the key event occurs. The factory setting is red LED and "line". The LEDs of a line key will:

• blink rapidly when a call is ringing on the line;
• glow steadily when there is an ongoing call on the line;
• blink slowly when a call is on hold on the line;
• be off when the line is free.

When other functions are mapped onto the keys, the LEDs may glow or blink. For example: When the "extension" function has been mapped onto a key and monitoring of extensions is enabled on both phones, the LED will

• blink rapidly when a call is ringing on the extension;
• glow steadily when the extension is busy;
• be off when the extension is not busy.