Before revision: These demodulate the signal from a modified marine VHF radiotelephone tuned to the AIS frequencies and convert into a digital format that the computer can read and display on a monitor; this data may then be shared via a local or wide area network via TCP or UDP protocols but will still be limited to the collective range of the radio receivers used in the network.
After revision: These demodulate the signal from a modified marine VHF radiotelephone tuned to the AIS frequencies and convert into a digital format that the computer can read and display on a monitor; this data may then be shared via a local or wide area network but will still be limited to the collective range of the radio receivers used in the network.