The Plug-in Power Supply Card has an input of 120 Vac or 130 Vdc to -48 Vdc output to power either a 5-card Shelf or the 8-card Shelf.
The Plug-in Power Supply Card (751318MC) will not work with older Model shelves, whose Model number ends in /13.
Two Plug-in Power Supply Cards may be installed in the 5 or 8 card Teleline shelf for redundancy. Each card is capable of providing the power required by a fully loaded shelf. When two cards are available, the load is shared by the two cards. If one of them fails, the other one takes over the full load without interruption of power.