32 CHAPTER 2: INSTALLING THE SWITCH
■ Network Jacks:
■ 3Com NJ95 (3CNJ95).
■ 3Com NJ100 (3CNJ100, 3CNJ100-CRM).
■ 3Com NJ200 (3CNJ200, 3CNJ200-CRM)
For the latest list of supported devices, go to the product page on the 
3Com web site 
http://www.3com.com/.
For further information about Power Over Ethernet, refer to “Power 
Management and Control” in the Switch Implementation Guide supplied 
on the CD-ROM that accompanies your Switch. PoE management is 
available using the web interface or the command line interface (CLI).
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 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 Ta b l e 7
.
WARNING: The 4400 PWR (3C17302) supports Power over Ethernet on 
all front ports. These ports should only be used for ethernet wiring within 
the same building.
Because of the PoE ability of the front ports of the Switch 4400 PWR 
(3C17205) these ports should only be used for ethernet wiring within the 
same building. The Rear Module ports of the Switch 4400 PWR, however, 
can be used for ethernet wiring between buildings. 
3Com recommends that you use Category 5 twisted pair cable — the 
maximum segment length for this type of cable is 100 m (328 ft).
DUA1720-3AAA05.book  Page 32  Friday, March 7, 2003  11:53 AM