Furuno FELCOM 12, Service Manual

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1-11
Ship-to-shore Message Transfer Steps
1. The MES normally receives via the NCS common channel, which contains network
configuration information (LES frequency, etc.).
2. The MES tunes to the shore-to-ship CES TDM frequency for the required LES.
3. The MES sends an "Assignment Request" packet on a signalling channel associated
with the CES TDM.
4. In response to the "Assignment Request" packet, the LES informs the NCS that it is
communicating with the MES.
5. The LES sends the MES an "Assignment" packet. This establishes the link between
LES and MES.
6. The MES sends the message on the assigned channel slot timing.
7. After the LES receives all messages it sends "Aknowledgement" to the MES.
8. This "Acknowledgement" packet contains a list of any packets that were missed or
received in error. Reception of an "Acknowledgement" packet prompts the MES to
retransmit any messages in error.
9. When all messages are received error free, the LES sends "Clear" to the MES and
tells the NCS that the MES is idle.