3Com 3C17203 - SuperStack 3 Switch 4400, Руководство по началу работы

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The Power-up Sequence 27
Connecting a
Redundant Power
System
You can connect a SuperStack 3 Advanced Redundant Power System
(3C16071B) to the Switch. This unit, which is also known as an RPS, is
designed to maintain the power to your Switch if a power supply failure
occurs.
For normal redundancy, the unit requires one Type 2A Power Module
(part number 3C16074A). For full redundancy, the unit requires two type
2A Power Modules combined using a Type 2 Y-Cable.
CAUTION The Switch has no ON/OFF switch; the only method of
connecting or disconnecting mains power is by connecting or
disconnecting the power cord.
CAUTION: The Switch can only use a SuperStack Advanced Redundant
Power System output.
Choosing the Correct
Cables
All of the ports on the front of the Switch 4400 are Auto-MDIX, that is
they have a cross-over capability. The port can automatically detect
whether it needs to operate in MDI or MDIX mode. Therefore you can
make a connection to a port with a straight-through (MDI) or a cross-over
cable (MDIX).
The Auto-MDIX feature only operates when auto-negotiation is enabled.
If auto-negotiation is disabled, all the Switch ports are configured as
MDIX (cross-over). If you want to make a connection to another MDIX
port, you need an automatic
cross-over cable. Many ports on
workstations and servers are configured as MDI (straight-through). If you
want to make a connection to an MDI port, you need to use a standard
straight-through cable. See Table 8 .
3Com recommends that you use Category 5 twisted pair cable — the
maximum segment length for this type of cable is 100 m (328 ft).
DUA1720-3AAA03_online.book Page 27 Monday, March 25, 2002 10:48 AM