What is the main physical interface on the VT310, and how is it used for setup?

What is the main physical interface on the VT310, and how is it used for setup?

The main connection is a 26-pin female connector (P1). For testing purposes, an optional 26 PIN All-in-one Test Cable is available, which connects to P1 and includes an open end (P2) that requires a 9-48V adapter for power.