Message Categories - Paradise Datacom P300-VSAT Installation & Operating Handbook

SA-bus
The SA-bus message structure has a different format for messages from Master to Slaves, and from
Slaves to Master.
Master to Slave
The message format is:
idle STX
(02H)
STX:
Address:
Instruction:
Body:
ETX:
Checksum:
Slave to Master
The message format is:
idle ACK / NAK
(06H/15H)
ACK/NAK:
Address:
Instruction:
Body:
ETX:
Checksum:

Message Categories

The remote M&C messages break down into the following categories:
1. Messages to read the configuration & reconfigure the unit
2. Messages to read the fault / operating status / performance of the equipment
3. Messages to read the current test mode & change the test status
4. Messages to request internally calculated values (eg data rates including overhead etc)
5. Messages relating to the remote M&C status
6. Messages relating to queries on the device itself, or option / cards fitted
7. Messages relating to the capabilities of the devices, and remote upgrading.
8. Message to perform an action (eg buffer centre)
9. Messages to change Tx power / carrier in an abbreviated form
10. Messages to read the traffic log
11. Administrative messages
The following table summarises all messages, including the message categories listed above. A detailed
list of the content of each message is available on request from Paradise Datacom.
P300H
Address Instruction `Body`
(31H-61H) (30H-7FH) (1st char)
The fixed character 02H
Slave Address, range 31H to 6FH (49-111 , ie 63 usable addresses).
Range 30H to 7FH. An ACK or NAK is automatically returned if the instruction is
received (or there is no response if the message is not received !).
From zero to 128 characters (resulting in a maximum message length of 132
characters).
The fixed character 03H
The Exclusive OR of the chars from the `STX` to `ETX` inclusive.
Address Instruction
(31H-61H) (30H-7FH) (1st char)
The fixed character 06H or 15H
As Master to Slave
Echo of the instruction to the Slave
NAK: One character, an echo of the instruction sent.
ACK: Where no response is expected (ie a `write` message), one character, an
echo of the instruction sent. Where a response is called for (ie a `query` message
resulting in a `read` response), the body is as defined for that response.
As Master to Slave
As Master to Slave
P300 Modem Installation and Operating Handbook
`Body` `Body`
(other chars) (last char)
10
`Body` `Body` `Body`
(other chars) (last char)
ETX Checksum
(03H)
ETX Checksum
(03H)
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