3Com 3CR17251-91 - Switch 5500G-EI Stackable Gigabit..., Руководство по началу работы

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The Power-up Sequence 41
Table 13 Unit Status Colors
If there is evidence of a problem, see “Solving Problems Indicated by
LEDs” on page 78 for a list of suggested solutions.
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.
Choosing the Correct
Cables
All of the ports on the Switch are Auto-MDIX, that is they have a
cross-over capability. These ports can automatically detect whether to
operate in MDI or MDIX mode. Therefore you can make a connection to
one of the ports 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 a
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 14 .
3Com recommends that you use at least Category 5 twisted pair cable —
the maximum segment length for this type of cable is 100 m (328 ft.).
Color State
Green The Switch is powered-up and operating normally.
Green flashing Self Test (POST) or Software Download is in progress.
Red The Switch has failed its Power On Self Test (POST).
Off The Switch is not receiving power.