SDT 5000 User Manual
Document MBUD-0109v11
‘Sub-addressing’ is a feature of the SDT 5000 where facilities in the SDT 5000 can be accessed
directly via X25. The ‘sub-address’ is appended to the base X25 address. These features include the
command server. The command server allows ‘commands’ to be sent via X25 with the responses
returned over X25.
With or without sub-addressing data can be sent to and from the RTU port on the SDT 5000. The
base X25 address without any sub-address refers to the RTU port.
The SDT 5000 uses the following sub-addresses for its various facilities.
Message Type
Caller Sub-address
Called Sub-address
Host to RTU
N/A
no sub-address, 0 or 1
Host to Command Server
N/A
2
RTU to Host
No sub-address
N/A
Alarms to Host
4
N/A
Table 1 – Sub-addressing for the SDT 5000.
When sending messages to a specific SDT 5000 facility the user’s host must attach the appropriate
called sub-address, given in
Table 1. The SDT 5000 will automatically attach the required caller sub-address when connecting to
the host. This enables the host to route the various types of SDT 5000 messages to separate
destinations.
The destination (host) address must be obtained from the host administrator of the system you wish to
connect.
Note: The SDT 5000 will ignore all packets that have the Q bit or A bit set to 1. For details on the Q-
bit or A-bit refer to the ISO 8208 specification.
4.2 Hardware
Overview
The SDT 5000 consists of a transceiver. an expansion board with terminal blocks and a high gain
antenna. The transceiver and logic modules, shown in
Figure 3, are housed in a lightweight chassis. The antenna module is connected to the transceiver
antenna port with a single internal co-axial cable. The transceiver module has an L-Band receiver, L-
Band transmitter modulator, up-converter and power amplifier. It incorporates a frequency
synthesizer with a high stability reference oscillator.
The unit operates with a 12V (nominal) DC supply. The following block diagram illustrates the main
hardware components of the SDT 5000 terminal.
Version 1.1, 03/24/06
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