Here is a look at the rear panel of the Axiom EP400 Epicenter Powered Subwoofer.
Beginning on the top and moving down the left side of the rear panel are the Input/Output connectionss, which include 2 line level/RCA phono jacks (1in/1out), 2 line level XLR jacks (1in/1out), and 1 set of standard speaker input terminals.
On the right side of the rear panel moving down are the Adjustment Controls. Included are Gain, Phase, Crossover (Defeatable), and Trim Controls. In addition, a USB Port provides for software/firmware updates.
On the bottom right of the rear panel are the power-related control and fuse, including the main power switch (which can be set for 110/120 or 220 voltage operation).
For a more detailed look and explanation of the connections and controls, proceed to the next series of photos.