support the use of Ethernet in bus topology via OFDM modulation, which enables several distinct data carriers to coexist in the same wire. Also, HomePlug's OFDM technology can turn off (mask) any sub-carriers that overlap previously allocated radio spectrum in a given geographic region, thus preventing interference. In North America, for instance, HomePlug AV only uses 917 of 1155 sub-carriers. Usage Powerline networking is a network that can be set up using a building's existing electrical wiring. For electric vehicle charging, the SAE J1772 standard plug-in electric vehicle charger also requires HomePlug Green PHY to establish communications over a powerline before the vehicle can begin to draw any charging power. All commercial HomePlug implementations meet the AES-128 encryption standard specified for advanced metering infrastructure by the US FERC. Accordingly, these devices are suitable to deploy as utility grade meters off the shelf with appropriate software. As of late 2012, the most widely deployed HomePlug devices are "adapters", which are standalone modules that plug into wall outlets (or power strips [but not surge protectors] or extension cords) and provide one or more Ethernet ports. In a simple home network, the Internet gateway router connects via Ethernet cable to a powerline adapter, which in turn plugs into a nearby power outlet. A second adapter, plugged into any other outlet in the home, connects via Ethernet cable to any Ethernet device (e.g., computer, printer, IP phone, gaming station). Communications between the router and Ethernet devices are then conveyed over existing home electrical wiring. More complex networks can be implemented by plugging in additional adapters as needed. A powerline adapter may also be plugged into a hub or switch so that it supports multiple Ethernet devices residing in a common room. Increasingly, the functionality found in standalone adapters is being built into end devices such as power control centers, digital media adapters, and Internet security cameras. It is anticipated that powerline networking functionality will be embedded in TVs, set-top boxes, DVRs, and other consumer electronics, especially with the emergence of global powerline networking standards such as the IEEE 1901 standard, ratified in September 2010. Several manufacturers sell devices that include 802.11n, HomePlug and four ports of gigabit ethernet connectivity for under US$100. Several are announced for early 2013 that also include 802.11ac connectivity, the combination of which with HomePlug is sold by Qualcomm Atheros as its Hy-Fi hybrid networking technology, an implementation of IEEE