GRT Avionics

With a Mini is it necessary to use both the RS-232 and ARINC-429 connections or would just the RS-232 work?

Both are required for approach display functions on any EFIS.

RS232 -- Provides basic GPS data including position, speed, and flight plan waypoints.

ARINC-429 -- Provides approach lateral and vertical deviation data, modes, autopilot commands (for GNAV mode), and additional GPS data including time and date.