(1) Short for power line communications, the use of the existing utility power grid as the medium to send broadband data communications. In theory, plugging a computer device into an existing power outlet would connect the user to the Internet by tapping into already established national and global power grid networks.
Power grids typically transmit electricity in three levels of voltage: low, medium and high. Medium voltage, typically ranging in the tens of thousands of volts, is what a utility substation will bring to a transformer, and the transformer will reduce the voltage into the low range before sending the electricity into a building. It is the low and medium voltages that PLC takes advantage of in order to transmit data at Ethernet-like speeds.
Some problems associated with the technology include no global technology standard, the different power usages of different countries, and the amount of noise that electronic equipment already produces on power lines.
PLC has applications in expansive networking, such as MANs or CANs, and smaller networking architectures, such as LANs and home networking.
(2) Short for product life cycle it is a marketing theory which dictates the the sequence of events, or lifespan divisions of any marketed product or brand, including technologies, consumer goods, and any item which is marketed to the public and sold at retail outlets on a national basis. Typically the PLC consists of four stages; introduction, growth, maturity and sales decline.