A cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. A headend facility may be staffed or unstaffed and is typically surrounded by some type of security fencing. The building is typically sturdy and purpose-built to provide security, cooling, and easy access for the electronic equipment used to receive and re-transmit video over the local cable infrastructure. One can also find head ends in power-line communication (PLC) substations and Internet communications networks.