Furuno FELCOM 12 Service Manual

1-7
1.3 Communications Network
The illustration below shows the Inmarsat-C network.
6
NCS/NCS
Signalling Channel
5
SES Signalling
Channel
Network
Coordination
Station (NCS)
Land Earth
Station
(LES) or
Coast Earth
Station
(CES)
Mobile Earth Station (MES)
Data Circuit
Terminating
Equipment
(DCE)
Data Terminal
Equipment (DTE)
EGC Received
Data landlines
Telex landlines
8
Landlines
3
CES TDM
Channel
4
SES Message
Channel
2
NCS/CES
Signalling Link
1
NCS Common Channel
7
1) NCS commom channel
This channel is transmitted continuously (24 hours/day) by the NCS. All SESs must be
tuned to the NCS common channel when not engaged in message transfer. Its main
functions are;
a. shore-to-ship message announcements
b. ship-to-shore message announcements
c. polling commands
d. EGC message transmission
e. login and logout acknowledgement
2) NCS/CES signalling link
This is the link between an NCS and all LESs in its region. Its functions are;
a. establishing initial signalling link between CES and NCS to transmit via the NCS
common channel
b. forwarding EGC message to NCS
c. forwarding NCS received distress alerts to LES.
3) CES TDM channel
This channel carries all signalling and message traffic to the SESs concerned with
message transfer with a particular LES.

Furuno FELCOM 12 Specifications

General

Brand	Furuno
Model	FELCOM 12
Category	Marine GPS System
Language	English