BROADBAND COMMUNITIES is the leading source of information on digital and broadband technologies for buildings and communities. Our editorial aims to accelerate the deployment of Fiber-To-The-Home and Fiber-To-The-Premises.
Issue link: https://bbcmag.epubxp.com/i/565727
AUGUST/SEPTEMBER 2015 | www.broadbandcommunities.com | BROADBAND COMMUNITIES | 65 source near these locations, or accessing that power may be problematic. For example, a network operator that seeks to mount cameras or APs on powered light poles would have to negotiate with the utility company to get access to that power – a process that can take months and eat into the revenue the operator expects to receive from implementing the service. Some utilities may require operators to install expensive power meters to track power consumption and then require periodic payments based on individual meter readings. Alternatively, an operator may want to put a camera on the side of a building but then would have to negotiate with the building owner for power. In any case, connecting to AC power requires an electrician to make the connection, which complicates the installation and adds time. 120VAC circuits may generally not be installed in the same conduits as communications cables because of electrical safety issues, so typically an AC connection must be installed in a separate conduit, adding expense and right-of-way issues into the mix. A confguration must usually then be custom engineered for converting AC to DC power, providing proper electrical protection for the outdoor environment, converting media properly (to GPON for most FTTx networks), connecting to the optical fber network and building ruggedized housing to install this equipment. PoE is a highly useful way of connecting and powering network devices such as HD video cameras and Wi-Fi APs. Because PoE functions within the low-voltage NEC Class 2 electrical code, PoE cables may be routed with other communications cables. However, the 100-meter maximum reach of PoE limits its applications. Some solutions exist to extend PoE marginally, but any real solution must bring power precisely where it is needed, even over considerable distances (up to a mile or more). Converting the GPON protocol to PoE is the second challenge. Even if local power is available, the FTTH network's optical signal must be converted to an electrical PoE signal to power and communicate with cameras and Wi-Fi hotspots. A media converter usually handles this function, but media converters are bulky and not typically ruggedized for outdoor use. POWERED FIBER CABLE AND POE EXTENDERS A powered fber cable combines single- or multimode fber with copper power conductors. Te cable system includes a rack-mounted power and optical fber termination point, the cable and a remote termination node for each device that plugs into the cable. (See Figure 1.) Te system functions on low-voltage DC within the NEC Class 2 electrical code, so the network operator needn't have an electrician install connections at the remote sites. Staying within NEC Class 2 also allows the cables to be routed as any communications cable – no extra conduit runs are required as needed in typical Class 1 (120VAC) circuits. In short, a powered fber cable system allows a network operator to Figure 1: A powered fber cable system