Communications Network - Furuno FELCOM 12 Operator's Manual

Communications Network

Data
Communications
Network
Telex Network
Terrestrial
Communications
Network
Figure 4 shows the Inmarsat-C communications network.
Network
Coordination
Station (NCS)
NCS/LES
Signaling Link
MES Signaling
Channel
Land Earth
Station
MES Message
(LES)
Channel
LES TDM
Channel
Figure 4 Inmarsat-C communications network
NCS common channel
NCS/LES signalling link This is the link between NCS and all
LES TDM channel
MES message channel
MES signaling channel This channel transmits requests, distress
NCS/NCS signaling link This is the link between NCSs. It ex-
NCS/NCS Signaling Link
NCS Common Channel
Mobile Earth
Station (MES)
Data Terminal
Equipment (DTE)
Data Circuit
Terminating
Equipment
(DCE)
Enhanced Group
Calling (EGC) Receiver
The NCS has two major functions:
1) Transmitting information on a com-
mon channel.
2) Transmitting EGC messages to MESs.
LESs in its region. All EGC messages
pass through this link.
This channel carries the circuit control
signal for MES and transmits messages
from LES to MES.
This channel carries messages from
MES to LES.
alerts, data reports, etc. In addition, it
carries login and logout from MES to
NCS.
changes data between MESs operating
in different ocean regions.
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