Power Line Carrier (PLC) is a unique power system of communication, power line carrier communication is the use of existing power lines, by-carrier analog or digital signals for high-speed transmission technology. The biggest feature is not required to re-set up the network, as long as there are wires, data transfer can be performed.
However, because of power line carrier communication has the following drawbacks, resulting in PLC main application - the "power line" failed large-scale applications:
1, distribution transformers for power line carrier signal has a barrier effect, so power line carrier signal can only be transferred within the region of a distribution transformer;
2, three-phase power line between a great signal loss (10 dB -30dB). When communications are very close, you may receive different phase signal. General power line carrier signal only single-phase power transmission line;
3 different ways to power line carrier signal coupling different signal loss, coupled mode cable - ground coupling and line - center line coupling. Line - ground coupling mode and line - neutral manner compared coupling, power line carrier signal loss less than ten dB, but the line - ground coupling mode is not suitable for all regional power systems;
4, existence itself some glitches due to power lines. Currently used are 50HZ AC and 60HZ, the period of 20ms and 16.7ms, in each AC cycle, two peaks, two peaks will bring two glitches that power line has a fixed pulse 100HZ or 120HZ interference, interference takes about 2ms, because given the interference must be addressed. There is a method for data transmission over 0:00 of the waveform in a short time, but due to over 0:00 time is short, the practical application of the AC waveform synchronized with poor control, modern communications data frame and relatively long, it is difficult to apply;
5, power line carrier signal on the high cut. When a heavy load power line, line up to 1 ohm impedance, resulting in high reduction of the carrier signal. Actual application, when the power line load, point-carrier signal can be transmitted to several kilometers. But when the power line load is heavy, it can only transfer tens of meters.
Although technical problems over time, can be resolved eventually be overcome, but the situation of the domestic broadband network construction now, leaving PLC's time and space is not generous. Since 2000 the major operators to roll out ADSL, optical fiber, wireless Internet and other broadband services, leaving power line living space, has other access methods are being squeezed. Now, PLC in addition to be used in the remote meter reading, but has not the original rhetoric.
With the rise of smart home systems this topic, but also to the PLC brought a new stage. In the current family of intelligent system to PC as the core of the family system is the most intelligent man touted. The system concept is that with the popularity of computers, data can be processed are all household appliances to computers to complete. This will need to build a data transmission network between the appliance and the PC, and now we are optimistic about the radio, but in a home in this environment, "multi-wall" this feature seriously affecting the quality of wireless transmission, especially in the villa and split-level The more obvious flaw residence. If you set up a dedicated wired network in addition to increased costs, the location of home appliances in the future can not move freely.
Most important feature of PLC: the need to re-set up the network, as long as there are wires, data transfer can be carried out, will undoubtedly become one of the best solution to this smart home data transmission. At the same time because the data transmission in the home only this range, bound five troubled PLC applications will cease to exist, the remote control of home appliances we also can connect to the traditional network PC then control appliances ways, PLC modem module The cost is far less than the wireless module.