Annex
1. What are wireless signals affected by?
1) Walls in the house with a limited space are the major barriers, as WLANapplies the wireless
microwave frequency band. The key feature of microwave is nearly linear transmission, with
terrible diffraction ability. Therefore, the wireless device behind the barrier receives weak
signals or even no signal.
2) Physical barriers not only obstruct the wireless microwave signals, but also absorb the
electromagnetic energyto generate weak current for leakage. So the floor with reinforced fabric
is the major metal barrier for wireless signals in the house. It is almost impossible for the
wireless signal to penetrate this barrier. Even if so, the signal is too weak.
3) The working frequency compliant with the standard IEEE 802.11b/g ( 2.4GHz). Most
industrial equipments support this working frequency, like microwave oven, Bluetooth device,
cordless telephone, or refrigerator. In case of any strong magnetic filed nearby, the wireless
network will be disturbed.
4) When two or more wireless devices work in the same environment, there could be channel
conflicts or wireless signal cross-talks.
5) Such strong signal interference sources as radio transmitter, welding machine, electric car or
high-voltage power transformer within 100m away from the wireless device or cable network
may also greatly interfere with the wireless signals or devices.
6) The weather may influence the wireless signals outdoor. Wireless signals are usually
weakened obviously in stormy or cloudy days and transmitted farther in sunny days.
2. Howcan we improve the signal transmission quality?
1) Select the best location to lay the wireless AP as described below:
First, it should be high enough to overcome the barriers and reduce the dead signal area.
Second, it should allowdirect signal transmission without walls acting as barriers. It is better
that the wireless AP is visible to the wireless client in your room.
2) Change the channel to reduce wireless cross-talks. Note: There should be at least 5
channels between your wireless signal transmitting channel and other people’s.
3) Reduce the interference from household appliances to smooth the signals. Lay the wireless
AP away from those appliances.
3. Preparation of Peer-to-peer (or Cross) Network Cable
1) Hold RJ45 (crystal head) to keep its clips downward, flat side upward, head outward, and
opening towards you. Then we number the 8 holes from left to right respectively 1, 2, 3, 4, 5,
6, 7, and 8.
2. Unpack one end of the twisted-pair jacketed and take any two strands (there are four strands)
out of the four (one strand in orange white and orange, and the other in green white and
green). Insert the four wires into the hole 1, 2, 3, and 6 of RJ45 in order, thereinto, 1+2 in a
strand (1: orange white; 2: orange) and 3+6 in the other strand (3: green white; 6: green).
Unpack the other end of the twisted-pair jacketed and take out two strands (there are four
strands) exactly same as the previous two. Insert the four wires into the hole 1, 2, 3, and 6 of
RJ45 in order, thereinto, 1+2 ina strand (1: green white; 2: green) and 3+6 inthe other strand
(3: orange white; 6: orange). That is, the second end is connected in a reverse way. All wires
form two overlapped crosses. (The hole 4, 5, 7, 8 are respectivelyfor wires in blue, blue white,
brown white, and brown, with two ends connected in the same way).
