The AIS computer keeps track of the timing for all groups and the timing of vessels tracked on channel 70. The system assures that channel 70 is operated in accordance with ITU-R recommendations with regard to channel loading. The AIS base at the appropriate time will initiate the sequence for vessels to report. As a vessel is reporting on the working duplex channel, the base is in repeater mode and is rebroadcasting location, course and speed as the vessel is sending. This allows the system to function as a collision avoidance tool.
Messaging is accomplished ship to shore, ship to ship and shore to ship.
An operator enters a free form text message, with its intended destination. The AIS computer recognizes a request to send from its own operator or a mobile and handles the transmission in appropriate packet sizes and times. All messages use the AIS tower. In this way if vessels are in the control area, they can receive and transmit messages to each other. With the AIS computer deciding on packet timing, there is a minimal time burden to the location reporting process.