M.T.H. Premier E94 Crocodile Operator's Manual page 39

To do this:
1. Call up the Front engine on your DCC system
2. To set the Front engine to respond to the Bell (F1), Horn (F2), Start-Up/Shut Down
(F3) and Front Coupler (F7) you will want to write a value of 71 to CV21. This is
setting bits 0, 1, 2, and 6 ON.
a. CV21's bits are shown in the table below – the decimal value is shown in
parenthesis:
Bit
(Decimal 7 (128)
Value)
F
F8
Function
6 (64)
5 (32) 4 (16)
F7 F6
Premier E94 Crocodile Electric Engine
3 (8) 2 (4)
F5 F4 F3
39
1 (2) 0 (1)
F2 F1