Presumably if the Captain-side buttons are lit red only B742/front_lamps/AP_reset_red_L and B742/front_lamps/AT_reset_red_L should have values of 1 and B742/front_lamps/AP_reset_yellow_L and B742/front_lamps/AT_reset_yellow_L should have 0 values (vice-versa for red and same applies for _R datarefs for the F/O's side. At least this is the case when the PTT buttons are pressed, in the sim PTT2 lights buttons red, PTT1 lights buttons amber.
Presumably if the Captain-side buttons are lit red only B742/front_lamps/AP_reset_red_L and B742/front_lamps/AT_reset_red_L should have values of 1 and B742/front_lamps/AP_reset_yellow_L and B742/front_lamps/AT_reset_yellow_L should have 0 values (vice-versa for red and same applies for _R datarefs for the F/O's side. At least this is the case when the PTT buttons are pressed, in the sim PTT2 lights buttons red, PTT1 lights buttons amber.