Black Box LPJ016A-TM Manual De Usuario
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What is PoE?
The seemingly universal network connection, twisted-pair Ethernet cable, has
another role to play, providing electrical power to low-wattage electrical devices
Power over Ethernet (PoE) was ratified by the Institute of Electrical and Electronic
Engineers (IEEE) in June 2000 as the 802.3af-2003 standard. It defines the
specifications for low-level power delivery — roughly 13 watts at 48 VDC —
over twisted-pair Ethernet cable to PoE-enabled devices such as IP telephones,
wireless access points, Web cameras, and audio speakers.
another role to play, providing electrical power to low-wattage electrical devices
Power over Ethernet (PoE) was ratified by the Institute of Electrical and Electronic
Engineers (IEEE) in June 2000 as the 802.3af-2003 standard. It defines the
specifications for low-level power delivery — roughly 13 watts at 48 VDC —
over twisted-pair Ethernet cable to PoE-enabled devices such as IP telephones,
wireless access points, Web cameras, and audio speakers.
Recently, the basic 802.3af standard was joined by the IEEE 802.3at PoE standard,
ratified inSeptember, 2009, which supplies up to 25 watts to larger, more
power-hungry devices. 802.3at is backwards compatible with 802.3af.
ratified inSeptember, 2009, which supplies up to 25 watts to larger, more
power-hungry devices. 802.3at is backwards compatible with 802.3af.
How does PoE work?
The way it works is simple: Ethernet cable that meets CAT5 (or better)
standards consists of four twisted pairs of cable, and PoE sends power
over these pairs to PoE-enabled devices. In one method, two wire pairs
are used to transmit data, and the remaining two pairs are used for
power. In the other method, power and data are sent over the same pair.
standards consists of four twisted pairs of cable, and PoE sends power
over these pairs to PoE-enabled devices. In one method, two wire pairs
are used to transmit data, and the remaining two pairs are used for
power. In the other method, power and data are sent over the same pair.
When the same pair is used for both power and data, the power and
data transmissions don’t interfere with each other. Because electricity
and data function at opposite ends of the frequency spectrum, they
can travel over the same cable. Electricity has a low frequency of 60 Hz
or less, and data transmissions have frequencies that can range from
10 million to 100 million Hz.
data transmissions don’t interfere with each other. Because electricity
and data function at opposite ends of the frequency spectrum, they
can travel over the same cable. Electricity has a low frequency of 60 Hz
or less, and data transmissions have frequencies that can range from
10 million to 100 million Hz.
PoE Solutions
Ethernet
Ethernet
Switch
PSE Unit
(LBPS01A-KIT)
Standard Unit
(LBPS01A-KIT)
Voice-Grade Copper Pair: 100/60 Mbps at 500 ft. (152.4 m)/
28/0.3 Mbps at 4000 ft. (1219 m)
LAN
LAN
PoE Power
LBPS01A-KIT
Ehternet Switch
PoE Repeater (LPR110)
PoE Repeater (LPR110)
PoE Device
PoE Power
PoE Power
PoE Power
100 m
100 m
100 m
LPR110
Basic structure.
There are two types of devices involved in PoE configurations: Power
Sourcing Equipment (PSE) and Powered Devices (PD).
Sourcing Equipment (PSE) and Powered Devices (PD).
PSEs, which include end-span and mid-span devices, provide power to PDs
over the Ethernet cable. A PoE PD access point derives its power from the
PSE Ethernet backhaul link. PDs are pieces of equipment like surveillance
over the Ethernet cable. A PoE PD access point derives its power from the
PSE Ethernet backhaul link. PDs are pieces of equipment like surveillance
cameras, sensors, wireless access points, and other devices that
receive power via PoE.
receive power via PoE.
When a PD is plugged in, it identifies itself as a PoE device with a
25-kilo-ohm resistor between the powered pairs. If the PSE detects
25-kilo-ohm resistance, it sends power; it if detects higher or lower
25-kilo-ohm resistor between the powered pairs. If the PSE detects
25-kilo-ohm resistance, it sends power; it if detects higher or lower