Feeling A Bit Power Hungry

wireless CAT5 cable switch

This type of wireless installation is particularly useful for roof-mounting of wireless bridges and access points, as usually there is no power outlet on a roof. It is also helpful because the access-point electronics can be placed near the antenna, reducing signal loss.

\

JOHN YACONO

Can be reached via e-mail at [email protected].

PoE is also useful in reducing cable clutter in data centers. A PoE switch can power remote hubs and other equipment so fewer,or at least tidier,power distribution units can be used. It also means cold-booting the switch by toggling its power can reboot all the network interconnections, which can be useful for devices lacking network management features. Repeaters in odd locations such as plenums likewise can be restarted.

If it's not feasible to replace a legacy switch for a unit offering PoE, power injectors can be used between the legacy switch and PoE devices.

Likewise, if at the far end of the network connection there is legacy equipment that could benefit from PoE but the devices are not capable of pulling power from their Ethernet connection, a PoE tap can be used to divert and condition the incoming power to load device's power plug.

id
unit-1659132512259
type
Sponsored post

The IEEE has a PoE standard called IEEE802.3af, which defines the distribution of 48 volts AC. The use of alternating current at that voltage allows long cable runs with negligible interaction with data in the same cable bundle. It also allows a wide variety of devices to take advantage of the specification. The standard also specifies which RJ45 pins to use.

Ironically, the truth about "standards" is that everyone gets to have their own. Keep in mind when selecting PoE devices that many manufacturers do not stick to the stated 48 volts AC specification. Sometimes they use their own pin configurations, too. Obviously, equipment can be damaged if the pins are mismatched.

What's your take on the new PoE devices? Let me know via e-mail at [email protected].