SDT 5000 User Manual
Document MBUD-0109v11
4. SYSTEM OVERVIEW
network
Ground Station
MSAT Satellite
Firewall
Host computer
Datahub
RTU
SDT5000
Firewall
Figure 2 - MSAT System Diagram
Figure 2 shows an overview of the basic MSAT architecture. The SDT 5000 relays messages, via the
MSAT satellite, between the RTU and the Data hub. The Data hub connects to the host system via
X25 over Frame Relay, XIP Gateway or another network.
4.1 X.25
The primary communication protocol implemented by the SDT 5000 is X25 as specified in the ISO
8208 specification. X25 allows for bi-directional data flow to the host from the RTU and from the
host to the RTU. The SDT 5000 is assigned an X25 address from the service provider. This address is
available with the command:
>x25dnic
3165
>x25addr
4612003235
The first 4 digits are referred to the DNIC; or network address. The remainder is the base X25 address
or node address. This is similar to a phone number that has an ‘area code’ and local number. The base
X25 address is a variable number of digits from 4 to 10 digits in length. If the base X25 address is
less than 10 digits the unit can support ‘sub-addressing’. The sub-address equivalent to an ‘phone
extension’.
Version 1.1, 03/24/06
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