I'm sure most of us on this forum understand the difference between a Cap and a Battery- size.
Why quibble? Performance of the Nortel product has proven their technology, and this is a case in point... We're talking about a product that was installed, probably, 20 years ago, and except for needing a little reprogramming when it takes a hit, works fine EVERY DAY.
Find me a PC, or server, or another phone system that can say the same.