electrical signal using thin film filter technology. These units require electrical power for their operation, so some providers connect them to backup batteries in case of power outages to ensure emergency access to telecommunications. The optical line terminations "range" the optical network terminals or units in order to provide TDMA time slot assignments for upstream communication. For FTTH and for some forms of FTTB, it is common for the building's existing ethernet, phone, and cable TV systems to connect directly to the optical network terminal or unit. If all three systems cannot directly reach the unit, it is possible to combine signals and transport them over a common medium such as Ethernet. Once closer to the end user, equipment such as a router or network interface controller can separate the signals and convert them into the appropriate protocol. For FTTC and FTTN, the combined internet, video and telephone signal travels to the building over existing telephone or cable wiring until it reaches the end-user's living space, where a VDSL or DOCSIS modem converts data and video signals into ethernet protocol, which is sent over the end-user's category 5 cable. See also National broadband plan References External links Fiber to the Home Council: Asia-Pacific Fibre to the Home Council: Europe Fiber to the Home Council: North America Fiber to the Home Council: Latin America Chapter Broadband Network architecture Fiber-optic communications Local loop Telephony Fiber to the premises de:Glasfasernetz de:Fiber In The Loop