18 INSTALLING THE SWITCH
If you are placing Switch units one on top of the other,
you must use the self-adhesive rubber pads supplied.
Apply the pads to the underside of each Switch, sticking
one in the marked area at each corner.
Place the Switch units on top of each other, ensuring
that the pads of the upper unit line up with the recesses
of the lower unit.
Supplying Power to the Switch
Power problems can be the cause of serious failures and
downtime in your network. Ensure that the power input
to your system is clean and free from sags and surges to
avoid unforeseen network outages. 3Com recommends
that you install power conditioning, especially in areas
prone to blackout, power dips and electrical storms.
The unit is intended to be grounded. Ensure it is
connected to earth ground during normal use. Installing
proper grounding helps to avoid damage from lightning
and power surges.
Before powering on the Switch, verify that the network
cables and the power cable are securely connected.
CAUTION: The Switch has no ON/OFF switch. The only
way to power on and power off the Switch is by
connecting and disconnecting the power cord. This is
called “power cycling”.
To power on the Switch:
1 Plug the power cord into the power socket on the rear
panel of the Switch. Refer to
“(7) Power Supply” on
page 13 for more information.
2 Plug the other end of the power cord into a power
outlet.
When the Switch is powered on, the Power LED lights
up. If the Power LED does not light up, refer to
“(5)
Power LED” on page 13 for more information.
Checking for Correct Operation
After you power on the Switch, it automatically
performs a power-on self-test (POST). During POST, the
Power LED on the front panel of the Switch flashes
green.
When POST is complete, the Power LED turns green. If
the Power LED turns yellow after POST, it means that
POST failed and the Switch has entered fail-safe mode.
The following summarizes the possible colors for the
Power LED after POST.
Status Meaning
Green The unit is powered on and ready to use.
Yellow Power-on self-test or loopback test failed. The
Switch is in fail-safe mode. This can happen if a
port or ports fail when the Switch was powered
on.