The Enhanced Frame Control Assembly is a 2N redundant power design, but with fewer components than the original frame control assembly found in earlier frame models. The enhanced frame control assembly has two redundant power supplies which are fed directly by independent dual ac line cords. The assembly is constructed with hot-swappable, redundant parts, which (along with the dual AC line cords) remove the possibility of a single part causing failure. If one power supply fails, the remaining power supply provides all of the power to all of the library's elements.The enhanced frame control assembly comes standard with Models L23 and L53, and can be ordered as a feature code for Models D23 and D53. The dual ac line cords are standard on Models L23, D23, L53, and D53, and do not have to be ordered separately.