Is there a way to easily solve the problems related to the installation of wireless APs? Power for the AP, Ethernet
Data for the AP, and being able to combine the two over distance can offer challenges to those who use Ethernet.
Many wireless installers have a similar problem, related to the necessity for a new power source provisioned for their remote equipment. This problem is typically dealt with by an electrician running separate circuits to the remote area. This can be costly, even prohibitive. For this reason and others, some installers have turned to inexpensive Power over Ethernet (POE) units.
The problem then becomes POE at a distance, over cabling. Using wires, voltage drops over distance. At 200 meters, you lose 4 or 6 volts. At 48VDC, you're left with 42 volts. Drop to 15VDC, and your Trango (News
) might not come up. By finding the resistance of the cable for a specific temperature, you can determine the amount of voltage drop over a distance.
Depending on the gauge, you will typically lose 6V per every 100 to 200 feet of wiring. Lower power translates to more amperage, which in turn means more heat and probable issues with the 24 gauge wires in CAT5. This may require the usage of 18 gauge wiring.
The problem of Ethernet distance limits for CAT3 - CAT6 can be challenging. Ethernet signals can reach a distance of 328 feet without degradation. You can probably get a little more distance out, depending on several interference factors.
One solution is the use of an Enable-IT 820 unpowered Ethernet extender, designed to carry Ethernet data over the standard 2-wire pairs and POE power over the spare pairs (pins 4/5 and 7/8).
Another solution is the reduction of the Ethernet line speed to 10Mb Full Duplex. This lowers the risk of packet collisions at distance. Use a low cost 10Mb switch to front-end your equipment at the head end if you need to.
Brian Solomon is a Web Editor for TMCnet, covering news in the IP communications, call center and customer relationship management industries. To see more of his articles, please visit Brian Solomon’s columnist page.
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