Button:

2 = (1964) A,AA,BB,CC on front/rear roof sign
3 = (1968) A,AA,BB,CC on front/rear roof sign
5 = exp/local on/off as display
6 = NR/SR Light On/Off
7 = Marker Light Changing
8 = NR on side
9 = SR on side
0 = Route on side