Power Saving Mode; Speed/Duplex - 3Com OfficeConnect 3CDSG8 User Manual

Ports

5.1.1 Power Saving Mode

The power saving modes allow the switch to reduce the amount of power it consumes by
monitoring the devices connected to the switch. There are two ways in which the switch can
save power: Sensing the cable length and powering down un-connected ports.
The Ethernet standard has been designed to operate over cable lengths of up to 100m (328
feet). However in many networks, the cables are much shorter, meaning much of the power
required to drive the signal over the full 100m distance is 'wasted'. This OfficeConnect® switch
is able to determine the length of the cable between it and the connected device. For short
cables below 30m (approx. 98 feet), the switch can reduce the strength of the signal while
maintaining correct operation. Between 30m and 70m (approx. 230 feet) the signal amplitude
will be increased compared to below 30m operation, but still with a power saving. Above 70m
full signal amplitude is applied and there is no power saving.
Note: When enabled, the cable length detection mode will determine the cable length every
time a cable is plugged into a port and link is established.
The switch is also able to determine if ports on the switch are unconnected. If this is the case
then the switch can power down the port on the switch to save the power that would normally
be wasted when no cable was connected. When a device is connected to the switch it will
power the port back up to ensure normal operation.
Note: The power saving modes have been rigorously tested to ensure that your OfficeConnect®
switch meets and exceeds all the applicable industry standards. When power saving modes are
being used you will not detect any loss of performance or reliability. You will be contributing to
the important task of reducing global energy consumption.
The Power Saving settings for the switch are set by a single drop-down list. The power saving
settings are applied to all ports. The possible values are:
• Full – Both cable length detection and port shutdown are enabled
• Link Up – Just the cable length detection mode is enabled
• Link Down – Just the port shutdown mode is enabled
• Disabled – None of the power saving modes are enabled

5.1.2 Speed/Duplex

The Speed and Duplex settings for the port are set by a single drop-down list. The possible
values are:
• Auto - Speed and duplex settings are auto-negotiated.
• 10HDX - 10 Mbps, half-duplex
• 10FDX - 10 Mbps, full-duplex
• 100HDX - 100 Mbps, half-duplex
• 100FDX - 100 Mbps, full-duplex
• 1000FDX - 1000 Mbps, full-duplex
Note: Auto is the default setting and need not be changed unless you are experiencing
problems establishing link with a connected device (i.e. the front-panel LEDs or SYSTEM >
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