Boeing 737

What is A/R on Boeing 737? (Altitude Rate)

What is BARO on Boeing 737? (Barometric)

What is CIS on Boeing 737? (Cabin Interphone System)

What is XFMR on Boeing 737? (Transformer)

What is B/C on Boeing 737? (Back Course)

What is PTT on Boeing 737? (Press To Talk/Push To Talk)

What is HDG REF on Boeing 737? (Heading Reference)

What is T OR TK OR TRK on Boeing 737? (Track)

What is FOD on Boeing 737? (Foreign Object Damage)