AT&T MERLIN LEGEND Installation & Maintenance Manual page 512

Maintenance and Troubleshooting
2. Press a fixed-feature button with one LED to toggle the LED
on and off.
Note: Mute and Speaker LEDs may not toggle consistently
since they are managed by both the CU and the telephone.
3. Press a fixed-feature button without an LED or press a
dialpad button to toggle the Message LED on and off.
4. Press the fixed-feature buttons and the dialpad in the
following sequence to turn on all the LEDs:
a. Volume down
b. Volume up
c. Transfer
d.
Conf
e. Drop
f. Hold
g. 123456789∗0#
MLX Telephones with Displays Test. Activating the test
blacks out the display.
Follow these steps to test an MLX telephone with a display:
1. Press any display button.
A unique character string should appear.
2. Press each display button in turn to cause a unique character
string to appear.
MLX Telephones with a DSS Test. Activating the test turns on
all the LEDs. Follow the steps in "Basic MLX Telephone Test"
above to get the LED response.
5-34 Maintenance