Ap1.1.5 Network - Nera Inmarsat-c Service Manual

AP1.1 System Overview

AP1.1.5 Network

Fig.AP1.1.3 shows the Inmarsat C channels and signals.
Fig. AP1.1.3 Channels and signals
NCS Common Channel
This channel is transmitted continuously (24 hours/day) by the NCS. The MES is
received the NCS common channel when not engaged in message transfer. Its main
functions are;
a. informing that the message is sent from the shore to MES.
b. informing the confirmation when MES sends the message to the shore.
c. polling commands.
d. EGC message transmission.
e. sending the acknowledgement for inquiry of Login and logout from MES.
f. Network information transmission.
LES TDM Channel (Time Division Multiplex Channel)
This channel is used to control the lines when the message is sent from LES to MES.
AP1-7