This decoder is not supplied with a speaker as the model is pre fitted with speakers Below is a list of the Function keys and their assignments applicable to this model. F0. Lights on /off F1. Sound on/off F2. Horn 1, two tone F3. Horn 2, two tone F4. Single horn F5. carriage door slam double F6. carriage door single F7. guard whistle F8 guard driver buzzer F9. flange squeal F10. rail joint noise ( changes speed with speed of train ) F11. shunt mode F12. Accel/decel override F.13 Aux 1 F.14 Aux 2 F15. seagulls F16. Coast. Press for coast, then press again and pick up throttle F17. Aux 3 F18. Aux 4