HomePlug and Powerline technology allow the internal wiring / cables of a building to be used in carrying an Ethernet signal for a local area network connection. To put it another way, these devices turn your existing power sockets into network ports without hassle.

Not to be confused with Powerline Communications (PLC); this allowed national grid operators to deliver broadband Internet connections over main power cables and into homes. This technology was trialled but ultimately abandoned in the UK due to its interference problems and inability to keep pace with competing services.