3com 4070 Guida All'Installazione Rapida
The Power-up Sequence
29
If there is evidence of a problem, see
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.
connecting or disconnecting mains power is by connecting or
disconnecting the power cord.
Choosing the Correct
10/100/1000 Cables
The 10/100/1000 ports on the front of the Switch 4050 and Switch 4060
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).
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
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
.
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).
the maximum segment length for this type of cable is 100 m (328 ft).
Table 7 Cables required to connect the Switch 4050/4060 to other devices if
auto-negotiation is disabled
CAUTION: If you want to install the Switch using a Category 5E or
Category 6 cable, 3Com recommends that you briefly connect the cable
to a grounded port before connecting network equipment. If you do not,
the cable’s Electrostatic Discharge (ESD) may damage the Switch's port.
Category 6 cable, 3Com recommends that you briefly connect the cable
to a grounded port before connecting network equipment. If you do not,
the cable’s Electrostatic Discharge (ESD) may damage the Switch's port.
You can create a grounded port by connecting all wires at one end of a
UTP cable to an earth ground point, and the other end to a female RJ-45
UTP cable to an earth ground point, and the other end to a female RJ-45
Cross-over Cable
Straight-through Cable
Switch to Switch
(MDIX to MDIX)
(MDIX to MDIX)
✓
✕
Switch to Hub
(MDIX to MDIX)
(MDIX to MDIX)
✓
✕
Switch to PC (NIC)
(MDIX to MDI)
(MDIX to MDI)
✕
✓
DUA1770-9AAA04.book Page 29 Monday, April 14, 2003 11:33 AM