UM380 03 010
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Switches and LEDs
3 Switches and LEDs
This chapter describes:
•
Operation of the switches on the rear panel
•
The information provided by the LEDs on the unit front panel
During normal operation of the unit the LEDs indicate its operational status. This information
is particularly useful in diagnosing cabling faults and external equipment problems, during
both installation and normal running.
3.1 Switches
3.1.1 Power ON/OFF switch
The power ON/OFF switch is located on the rear panel adjacent to the mains connector. It
switches mains electricity to the Universal Input Power Supply Unit.
3.1.2 Sync switch
The Sync switch allows the unit clock source to be synchronised to either of the primary
ports (P1 or P2). It is located on the rear panel between the Alarm connector and the
Ethernet connector. The selection must be made before power is applied to the unit.
Ideally, the Sync switch should be set to whichever port is connected to the network so that the
unit is synchronised with a central clock source rather than the clock source of another unit.
However, in a Packet Switched Network the synchronisation should come from the PBX.
3.1.3 Port Impedance switches
The Port 1 and Port 2 impedance switches allow the selection of either 75W or 120W
impedance to be made. They are located adjacent to the Port 1 and Port 2 connectors on
the rear panel. The selection should be made before power is applied to the unit.
3.2 Front Panel LEDs
The unit has 10 LEDs on its front panel. During the self test sequence, and in the event of an
alarm, they show unit status information.
3.2.1 Status LEDs
There are 4 red Status LEDs; S3,S2,S1 and S0. They indicate unit status in conjunction with
the two port LEDs, P1 and P2. During unit self-test, the status LEDs will come on and go off
in sequence and in the event of a self-test failure, stop with one LED remaining on.
