I prewired my panel for the AF Pilot a couple years back, with the serial input to the AP head fed from the AF-GPS signal, according to the wiring plan I had at the time. (I have no IFR navigator, only the AF-GPS for position source.)

Now I'm getting around to installing the autopilot and see the more current diagrams call for four connections to the AP head:
- ARINC in & out from converter
- RS-232 in & out from EFIS serial port

Does the AF Pilot require the discrete RS-232 comm with the 4500s EFIS? What features are gained/lost by connecting it that way, instead of feeding the NMEA signal direct from the GPS? Will it function at all without?

My other devices are VPX Pro, GTX327, and CO Guardian (which could be dropped if necessary). Proposed serial port plan for comments:
Serial 1 ARINC
Serial 2 CO Guardian -OR- AF Pilot ???
Serial 3 VPX Pro
Serial 4 Icarus/NMEA

Thanks ~