7
P
ROBLEM
S
OLVING
The OfficeConnect switch has been designed to help
you detect and solve possible problems with your
network. These problems are rarely serious; the cause
is usually a disconnected or damaged cable, or
incorrect configuration. If this section does not solve
your problem, contact your supplier for information
on what to do next.
Perform these actions first:
Q
Ensure all equipment is powered on.
Q
Power each unit off, wait about 5 seconds and then
power them on.
Check the following symptoms and solutions:
Power LED not lit.
Check your power adapter
connection. If there is still no power, you may have a
faulty power adapter which needs replacing with an
identical OfficeConnect power adapter.
Do not use
any other power adapter with the switch.
Port Status LED not lit for a port that has a
connection.
There is a problem with this connection.
Check that you are using a ‘straight-through’ cable
which is properly connected at both ends, and is not
damaged. Also check that the equipment being
connected to the switch is powered on, operating
correctly and contains the correct type of connection.
Alert LED continuously lit.
If the Alert LED is lit,
there is a problem with the network. Starting with
the 10/100BASE-TX ports, remove the port
connections one at a time, waiting a few seconds
between each port. If the Alert LED goes off, there is
either a network loop or an excessive amount of
broadcast traffic on that port connection:
Q
Network loop — Examine your connections and
remove the loop. Each piece of equipment needs
only one connection to your switch.
Q
Excessive amounts of broadcast frames — Some
pieces of network equipment operate by sending
out broadcast frames regularly. Refer to the
documentation that accompanies the piece of
network equipment.
If the Alert LED is still lit after removing all of your
connections, there may be a problem with your unit.
Power it off, wait about 5 seconds and then power it
on. If the Alert LED comes back on continuously,
contact your supplier.
Link between the switch and an OfficeConnect
hub not working.
Check your connections; follow
the information given in the
OfficeConnect Hubs to Your Switch”
section. It is
likely that an MDI/MDIX switch is incorrectly set on
the switch (for 100BASE-TX) or hub (for 10BASE-T).
Full Duplex LED not lit when the switch is
connected to another full duplex device (adapter
card or unit).
If the connected device does not
support auto-negotiation, the switch will operate in
half duplex mode (even if the device is operating in
full duplex mode). In such a configuration, you may
notice some degradation of network performance.
3Com recommends that you use devices that are
capable of auto-negotiation.
Dimensions and Operating Conditions
OfficeConnect Switch 280
Standards
Functional:
ISO 8802/3
IEEE 802.3
Safety:
UL 1950, EN 60950
CSA 22.2 #950, IEC 950
EMC:
EN 55022 Class B*
EN 50082-1
FCC Part 15 Class B*
ICES-003 Class B*
VCCI Class B*
AS/NZS 3548 Class B*
* Screened (shielded) cables must be used to ensure
compliance with these EMC standards. Refer to the
section for conditions of
operation.
Environmental:
EN 60068 (IEC 68)
Acoustic Noise:
ISO 7779
ISO 9295
D
IMENSIONS
AND
S
TANDARDS
