There are two kinds of power supply inputs for an Abacus 13-slot chassis. They are:-
1. A.C. input. This is the main input for Abacus. Abacus has power supply units converting this A.C. input into the desired DC power supplies for the system.
2. 48VDC Input. If you have XCG or ECG requiring to perform Ground Start Signaling, you need to have an external 48VDC Input.