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Chapter 4: Making Network Connections
Connecting Network Devices
These switches are designed to interconnect multiple segments (or collision
domains). They can be connected to network cards in PCs and servers, as well as to
hubs, switches or routers. They may also be connected to devices using optional
SFP tranceivers.
If 802.3af-compliant PoE devices are connected to the switch's
10/100 Mbps ports, the switch automatically supplies the required power.
Twisted-Pair Devices
Each device requires an unshielded twisted-pair (UTP) cable with RJ-45 connectors
at both ends. Use Category 5, 5e or 6 cable for 1000BASE-T connections, Category
5 or better for 100BASE-TX connections, and Category 3 or better for 10BASE-T
connections.
Power-over-Ethernet Connections
The PoE switch automatically detects an 802.3af-compliant device by its
authenticated PoE signature and senses its required load before turning on DC
power to the port. This detection mechanism prevents damage to other network
equipment that is not 802.3af compliant.
Note: Power-over-Ethernet connections work with all existing Category 3, 4, 5, 5e or 6
network cabling, including patch cables and patch-panels, outlets, and other
connecting hardware, without requiring modification.
The switch delivers power to a device using the two signal wire pairs in UTP or STP
cable (RJ-45 pins 1, 2, 3, and 6). The switch can provide up to 15.4 W of power
continuously on each 10/100 Mbps port. However, taking into account some power
loss over the cable run, the amount of power that can be delivered to a terminal
device is 12.95 W. If a device draws more than 15.4 W, from a port, an overload
condition occurs and the port turns off the power.
The switch controls the power and data on a port independently. Power can be
requested from a device that already has a data link to the switch. Also, the switch
can supply power to a device even if the port's data connection has been disabled.
The power on a port is continuously monitored by the switch and it will be turned off
as soon as a device connection is removed.
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