Furuno FELCOM 12, Руководство по обслуживанию

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1-12
2. Shore-originated Call
The following describes how a subscriber to the public telecommunications networks can
send a message to an MES.
MES
LES
NCS
NCS CC
(Announcement)
(MES Status: busy)
CES TDM
(Message)
(Acknowledgement)
(Clear)
ISL
(MES Status
:
idle)
END
Tunes to NCS CC
Receives update on BB and
tunes to CES TDM channel.
And decodes BB & SCD.
Tunes to SES
signalling channel
Tunes to CES TDM
channel
Re-tunes to NCS CC
Tunes to SES signalling
channel
ISL
NCS updates data on this MES
to busy.
NCS updates data base.
(MES status changed to idle)
Message Reception
Terrestrial
subscriber
Call
Check if MES is logged-in.
Message
Stores all message.
ISL
(MES Status Request
+ Announcement)
Check of MES status.
• not in the region
• Idle
• Busy
(MES Status)
When MES is idle.
ISL
(MES Status
:
Announcing)
(Assignment Response)
SES Signalling Channel
Receives all messages
and finds packets in
error.
(Acknowledgement Request)
Retransmits any packets
received by MES in error.
After 60 sec.
CES TDM
SES Signalling Channel
CES TDM
Tunes to CES TDM
NCS CC
SCD) Signal Channel Descriptor Packet
ISL) Interstation Signalling Link
BB) Bulletin Board