Comparison With Other Integrated Data and Power Standards
PoE provides both data and power connections in one cable, so equipment doesn't require a separate cable for each need. For equipment that does not already have a power or data connection, PoE can be attractive when the power demand is modest. For example, PoE is useful for IP telephones, wireless LAN access points, cameras with pan tilt and zoom (PTZ), and remote Ethernet switches. PoE can provide long cable runs e.g., 100 m (330 ft) and deliver 12 W of galvanically isolated power. PoE-plus provides even more power.
There are competing technologies. The Universal Serial Bus (USB) provides both data and power, but it is designed for short cables with a maximum length of 5 m (16 ft) and provides less than 2.5 W of non-isolated power. It is less expensive than PoE, and works well for low power peripherals such as a computer mouse, a headset/microphone, or a serial port. Some peripherals, such as speakers, scanners, and printers, need more power than USB can provide. Firewire (IEEE 1394) is similar to USB, but can provide substantially more power (45 W) but has an even shorter limit on cables at 4.5 m. On the other hand, USB peripherals can operate using very little power; while maintaining an Ethernet connection uses a significant amount of power.
If a device already has power available but no data link, then PoE may not be attractive. A wireless data connection such as IEEE 802.11 may be more economical than running a data cable for the device. Alternatively, there are power line communication technologies that can use power cables for transmitting data. Using some power line modems may be more economical than running a cable.
When data rate and power requirements are both low, other approaches may be viable. Mobile phones, for example, use batteries for power and microwave antennas for communication. Remote weather sensors use very low data rates, so batteries (sometimes supplemented with solar power) and custom wireless data links are used.
Depending on the application, some of the advantages with PoE over other technologies may be:
- Inexpensive cabling
- Fast data rate
- No batteries required
- Peer-to-peer network access. Once a device is connected to the network, it is accessible to many users.
Read more about this topic: Power Over Ethernet
Famous quotes containing the words comparison with, comparison, integrated, data, power and/or standards:
“I have travelled a good deal in Concord; and everywhere, in shops, and offices, and fields, the inhabitants have appeared to me to be doing penance in a thousand remarkable ways.... The twelve labors of Hercules were trifling in comparison with those which my neighbors have undertaken; for they were only twelve, and had an end; but I could never see that these men slew or captured any monster or finished any labor.”
—Henry David Thoreau (1817–1862)
“From top to bottom of the ladder, greed is aroused without knowing where to find ultimate foothold. Nothing can calm it, since its goal is far beyond all it can attain. Reality seems valueless by comparison with the dreams of fevered imaginations; reality is therefore abandoned.”
—Emile Durkheim (1858–1917)
“Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
—Talcott Parsons (1902–1979)
“To write it, it took three months; to conceive it three minutes; to collect the data in it—all my life.”
—F. Scott Fitzgerald (1896–1940)
“Here far from the city we make our roadside stand
And ask for some city money to feel in hand
To try if it will not make our being expand,
And give us the life of the moving-pictures’ promise
That the party in power is said to be keeping from us.”
—Robert Frost (1874–1963)
“Men are rewarded for learning the practice of violence in virtually any sphere of activity by money, admiration, recognition, respect, and the genuflection of others honoring their sacred and proven masculinity. In male culture, police are heroic and so are outlaws; males who enforce standards are heroic and so are those who violate them.”
—Andrea Dworkin (b. 1946)