ul or broadband access-BPL can be used as a broadband access, or local loop, alternative. Indoor short-haul or home area networking-Home area networking refers to the use of powerline within the home or residence domain. (HANs are covered in detail later in this chapter.) Automotive applications-Automotive applications enable in-vehicle net- work communications-whether voice, data, video, or music signals-by digital means over direct current (DC) battery powerline. The automotive applications include mechatronics (for functions such as obstacle detec- tion, door control, and climate control) as well as support for telematics and multimedia. PLT Architecture As shown in Figure 12.9, PLT works by injecting the digital connection into the powerline on the consumer side of a low-voltage substation. The injection point Broadband PLT Each customer site requires a PLT modem CPE Any other access containing an appropriate chipset. technologies can use residential gateway features. Headend injects signal coming from the xDSL or backbone. Modem Powerline Backbone A high-speed PLT modem Residential gateways enable several nodes to connect containing a chipset is installed to a LAN and share the high-speed connection. in MV/LV transformer. Efficient LAN-to-LAN frequency reuse is achieved. MV/LV = Medium Voltage/Low Voltage Figure 12.9 An example of PLT is connected to a fiber backbone by any appropriate means. This could be a wire- less connection in a rural area or a DSL or cable modem in an urban area. Utility companies use conditioning units that act as multiplexers to transmit low- and high-frequency signals. The lower-frequency signals carry power, and the higher- frequency signals carry data and voice. The conditioning units are part of a high- frequency conditioned power network (HFCPN) and send signals to outlets in the home or office. These signals are received by boxes similar to cable modems in the home and can link numerous devices, from microwave ovens to PCs. When PLT technology is used to provide broadband Inte