HomePlug AV2 specification was introduced in January 2012. It is interoperable with HomePlug AV and HomePlug GreenPHY devices and is IEEE 1901 standard compliant. It features gigabit-class PHY-rate, support for MIMO PHY, repeating functionalities and power saving modes. It can additionally use the band from 30 to 86 MHz. The first generation are generally considered to be 20% faster than HomePlug AV 500, it is often sold as HomePlug 600. They do not support MIMO, but only single streams due to the Atheros chipset architecture (QCA7450/AR1540). October 2013 Qualcomm announced the QCA7500 with support for 2x2 MIMO which supposedly will double data transfer rates. In 2014, Qualcomm began production of the QCA7500. This device provided raw PHY rates of 1300 Mbps, with resultant data rates of 550 Mbps UDP and 500 Mbps TCP, full MIMO. Communication takes place on both the line–neutral and line–ground power line pairs. Devolo from Germany has made proprietary improvements on the standard, and are using the ground wire in addition to phase (also known as hot or live) and null (also known as neutral). This technology is available world wide, though can only be used in territories that use the ground wire in their building wiring regulations. HomePlug Green PHY The HomePlug Green PHY specification is a subset of HomePlug AV that is intended for use in the smart grid. It has peak rates of 10 Mbit/s and is designed to go into smart meters and smaller appliances such as HVAC thermostats, home appliances and plug-in electric vehicles so that data can be shared over a home network and with the power utility. High capacity broadband is not needed for such applications; the most important requirements are low power and cost, reliable communication, and compact size. GreenPHY uses up to 75% less energy than AV. The HomePlug Powerline Alliance worked with utilities and meter manufacturers to develop this 690-page specification. HomePlug Green PHY devices are required to be fully interoperable with devices based on HomePlug AV, HomePlug AV2 and IEEE 1901 specification, which is considered to hamper their power consumption and cost reduction. The HomePlug silicon vendor QualComm announced commercially available Green PHY silicon on December 2011. HomePlug GreenPHY is the communication protocol used in the international electric vehicle charging standard CCS HomePlug Access BPL Access Broadband Power Line (BPL) refers to a to-the-home broadband access technology. The HomePlug Alliance formed the HomePlug Access BPL