AMiT audio control units (communication gateways) provide the system for:
- Public announcements within the vehicles
 - Telephone line for establishing a connection and communication with the driver
 - Radio telephone line for establishing a connection and communication with the control center
 
The connection of the control unit to the train’s audio system is ensured according to the interface specified in UIC 568.
Basic functions
- Public announcement system
- Switching announcements between a single carriage and the entire train
 - Option to select priority announcement mode
 - Remote control of the audio system in all carriages
- Switching on and off of speaker systems
 - Volume control for priority announcements
 
 - Setting maximum volume for priority announcements
 
 - Microphone input for spoken announcements and telephone lines
 - Communication with compartment units via RS485 serial line