Span power-powering new services economically and safely

Span powering has been used effectively since the advent of T1 repeaters. Over the years, various choices of operating voltage and practices such as utilizing only negative voltages have served the telecom industry well. As with every other aspect of our business, this is changing. New services utilizing various forms of DSL now require increased power levels. To be economical, this power must be delivered at increased distances from the CO or power cabinet. Span powering offers one method to significantly reduce system deployment costs. This paper will discuss various application considerations, review architecture choices, and provide an update on such critical issues as safety and regulatory approval including the recently released UL/CSA 60950-21. Based on this, we will compare several integrated span powering systems, highlighting application related advantages and recommending safety related practices.