554 Matrix ETERNITY NE System Manual
The following table shows the relationship between the colour of the LED and various events:
• Green indicates the state of the extension/trunk you access. For example, when you make a call to 
another extension 203, the LED of the DSS key assigned to Extension 203 blinks Green to indicate 
ringing at the extension. If you have successfully established speech with Extension 203 the LED glows 
Green continuously.
• Red indicates the state of other Extensions/Trunks. For example, if the LED of the DSS key assigned 
to Extension 201 is glowing Red continuously, it means Extension 201 is busy with another Extension 
or Trunk.
• Orange indicates the state of the trunk you are in speech with. For example, when you are in speech 
on an outgoing call on Trunk 1 the LED of the DSS Key assigned to Trunk 1 will be continuously ON. 
When you put the call on hold, the LED will blink slowly.
The LEDs of DSS Keys that are designated as Call Appearance (CA) Keys will function as follows:
• Status of Features: The LED of a DSS key is activated when the feature assigned to this key is used.
The LED of DSS keys assigned to Extensions/Trunks glow in a single colour - Red - to indicate status 
of the call event on the Extensions/Trunks and on the DKP.
• Not all features require LED indication. Hence the LED on a DSS Key is activated only if the feature 
assigned to that key requires LED. 
• For example, Call Pickup; this feature does not require an LED. So when a DSS key is assigned to this 
feature, the LED of the key remains inactive, when Call Pickup feature is used. 
LED 
Colour
LED Mode
Continuously ON Slow Blink Fast Blink
Green The key assigned to the 
Extension you are in 
speech with.
The key assigned to the 
Extension you have kept on 
hold.
The key assigned to the 
Extension you are calling or from 
which you are being called.
Red  The key assigned to the 
Extension that is now 
busy with another 
Extension/Trunk.
The key assigned to the 
Extension which has put 
another Extension/Trunk on 
hold.
The key assigned to the 
Extension/Trunk that is called or 
being called by another.
Orange You are talking on a 
Trunk (external call)
You have held a Trunk 
(external call)
You have an incoming call on the 
Trunk (external call)
LED 
Colour
LED Mode
Continuously ON Slow Blink Fast Blink
Green When you are in speech 
with a Extension (internal 
call)
When you have put a 
Extension on hold (internal 
call)
When any Extension is 
calling (internal call)
Orange When you are in speech 
with Trunk (external call)
When you have put a Trunk 
on hold (external call)
When any Trunk is calling 
(external call)