Power Line Communication is a fairly recent technology which is used to transfer data and establish means of communication at broadband speeds over transmission lines. The technology is widely also known as Power Line Telecommunication (PLT) or even Power Plus Communications (PPC). The technology uses advanced modulation technology which super imposes the data signal of high frequency over the low frequency power signal.
The research into PLC started off in the mid 1980’s in the band range of 5-500 KHz and was developed for only unidirectional communication but with time the system has been advanced to permit bidirectional transmission of data signal.
Since this fast system enables transmission in the form of voice and other data as well it has wide implications. Since most forms of communication today require separate hard wiring it is convenient to use PLC which can employ the pre-existing power cables within the house. Since the power in these cables is AC (alternating Current), it can be employed for various bidirectional modes of communication as well.
Such a communication system can be used for the monitoring and also the controlling of various fundamental functions like energy management, security, and safety control applications at homes, factories, offices, aircraft etc. The Transmission companies use this type of transmission to synchronise the operations in various substations and to monitor the power supply at the consumer end. PLC systems include a transmitter unit competent of sending (transmitting) communication signals over the Power line signal and also have a receiver unit at the receiving end which separates the communication signal and the power signal.
The transmitter generates modulated RF signal at the sending end this signal is then demodulated at the receiving end. A power line communication modem is used to convert digital data from an information processing unit like a computer to analog data; these modems play a crucial role by helping the sending and receiving units to communicate with one another.
Like any modern technology the PLC system also suffers from various constraints, the technology is still not sufficiently advanced to take advantage of all the benefits that it has promised. Also since the PLC network is a electrical supply network and telecommunications network it comes under certain jurisdictions and legal frameworks. But since the technology is new there are not enough guidelines in place, for its proper running and installation. Interference issues are also a major concern that is since the signal is over lapping with lower frequency power signal; there is always an issue of improper decoding. The power wiring system was formerly intended for the transmission of Power, the power wire circuit usually has limited ability when it comes to carrying higher frequencies in which the data signals are encoded.