Bell codes, buzzer codes or Communication Signal Appliance codes entail a series of bells or buzzers used on passenger trains for communication between the driver and guard.
All codes, except 3âÂÂ2âÂÂ1, must be acknowledged by repeating the code received.
In Japan, these are known as In-Car Communication Signals (). Each code must be acknowledged by the receiver. Examples of common railway bell codes are:
In the United States, these are known as Communication Signal Appliance codes.