737AvEng,
Section 22-31-00 pages 28,29,30 dated 10/10/06
3 schematics entitled AT SYSTEM-DIGITAL INPUT INTERFACE
One shows RA#2 having a direct(not via FCC b)input interface with AT CMPTR.
Effectivity is:
GEF 002, 003, 006, 007, 009, 011, 012, 028, 030, 301-305, 309-399, 713, 714, 717, 719, 721-726, 728, 729, 733, 735, 737, 805, 810, 811, 817, 821, 826-829, 833, 834, 837, 839, 840, 843,848, 859-861; GEF 812, 825 POST SB 737-34-1758; GEF 815 POST SB 737-34-1941
Other two schematics show input to FCC B.
Hope you can make more sense of it than I can.
Yes,I see AoA indicator is an option.I have not seen one installed myself.