A simulated optical network unit for battery characterization in the outside plant

With the arrival of fiber in the local subscriber loop, local exchange companies (LECs) are facing the need for placing an optical network unit (ONU) at or near each. To show that ONU design objectives can be met at reasonable cost when higher grade cells are used in a properly designed and maintained battery system, Bellcore has initiated a field demonstration of batteries powering simulated ONUs in the outside plant. A brief review and assessment of batteries in an ONU environment is presented first; this assessment includes secondary valve regulated lead acid batteries and nickel cadmium batteries. Based on this assessment, high-temperature nickel-cadmium batteries where chosen to provide power back-up for the simulated ONUs. The design of the ONU demonstration, including the battery charge/control electronics and the monitoring and control system, is then discussed. Finally, initial data from the field demonstration involving 10 ONUs are presented and discussed.<>