Quick Instruction, Version 2.2
Page 9 of 43 pages
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An "assigned" mode for operation in an area subject to a compe-
tent authority responsible for traffic monitoring such that the data
transmission interval and/or time slots may be set remotely by that
authority;
A "polling or controlled" mode, where the data transfer occurs in
response to interrogation from a ship or competent authority.
This illustration depicts a typical AIS System, where two or more AIS
equipped vessels (and shore based systems) are automatically communi-
cating with each other.
The following sketch shows a typical easyTRX2 installation in a common
environment. The easyTRX2 is connected to the vessels power supply,
and in connection with the VHF, and GPS-Antennas, the minimal re-
quirements for Transponder operation are fulfilled.
Both vessels in this illustration are equipped with an AIS transceiver.
Due to “Time – Synchronization” they use the same organization of free
and allocated windows (Slots) in the shared VHF Data Link (this method
is called “Carrier Sense Time Division Multiple Access”) to send and re-
ceive messages. Without the necessity of any operating interaction, both
