| Communication through Power Lines: what's that? |
 Power line communication (PLC) has been developed to create an effective communication network using the same electrical infrastructure that supplies all the network elements, without adding any new unnecessary and expensive cables or radio frequency systems.
A narrowband communication over power lines is sufficient for simple information exchange as measure, command to actuators, check system and so on, allowing a wide number of applications both in outdoor and indoor environments.
For example, utilities can use the outdoor network for remote street lighting control and monitoring or for Automatic Meter Reading (AMR) and Management (AMM), providing at the same time many client services like power consumption control and tariff selection.
On the other side, the indoor electrical grid can be used to connect home appliances realizing home or building automation, security and safety systems, temperature and lighting fixtures control.
| So how does a Power Line Modem work? |
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Special devices known as Power Line Modems (PLMs) are required for robust communications over power cables where strong and unpredictable noise and losses are present.
Like ordinary modems, a modem suitable for use over power lines is able to convert a binary data stream into a sequence of signals with predefined characteristics (frequencies, levels) and vice versa converts them back into the binary data stream, making the modulation / demodulation process. |
Furthermore, they must be able to convey the modulated signals over the physical mean (the power line in our case or the telephone line in case of "standard" modems) and detect arriving signals, making the transmission/receiving process.
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