The CiscoAS5850 is equipped with two power-entry modules (PEMFs), which accept DC-input power either from your site DC source or from an optional AC-input power shelf, and distribute -48 VDC to -60 VDC power to the chassis components using the back plane. The PEMFs provide power redundancy and load sharing; however, a single PEMF can power a fully configured system. The PEMF also contains a passive DC power filter, which includes a broadband electromagnetic interference (EMI) filter and circuitry for monitoring power coming into the chassis.