NAL Research Corporation (TN2012-02-V1.0)
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The <SBD message length> parameter represents the length, in bytes, of the SBD
message not including the mandatory two-byte checksum.
The maximum mobile originated SBD message length is 1960 bytes. The minimum
mobile originated SBD message length is 1 byte.
Once the Dte receives the READY indication from the A3LA-RS, the SBD message must
be sent from the DTE formatted as follows:
{binary SBD message} + {2-byte checksum}
o
The checksum is the least significant 2-bytes of the summation of the
entire SBD message. The high order byte must be sent first. For example if
the DTE were to send the word “hello” encoded in ASCII to the A3LA-RS
the binary stream would be hex 68 65 6c 6c 6f 02 14.
o
The mobile originated buffer will be empty upon power-up.
If any data is currently in the mobile originated buffer, it will be overwritten.
Command Response:
0: SBD message successfully written to the A3LA-RS.
1: SBD message write timeout. An insufficient number of bytes were transferred to
the A3LA-RS during the transfer period of 60 seconds.
2: SBD message checksum sent from DTE does not match the checksum calculated at
the A3LA-RS.
3: SBD message size is not correct. The maximum mobile originated SBD message
length is 1960 bytes. The minimum mobile originated SBD message length is 1
byte.
A.8.86 +SBDRB – Short Burst Data: Read Binary Data
Exec Command:
+SBDRB
This command is used to transfer a binary SBD message from the single mobile terminated
buffer in the A3LA-RS to the DTE. The mobile terminated buffer can contain only one message
at any one time.
The SBD message is transferred formatted as follows:
{2-byte message length} + {binary SBD message} + {2-byte checksum}
o
The {2-byte message length} field represents the length, in bytes, of the SBD
message not including the length field or the mandatory two-byte checksum.
The high order byte will be sent first.
o
The maximum mobile terminated SBD message length is 1890 bytes.
o
The checksum is the least significant 2-bytes of the summation of the entire
SBD message. The high order byte will be sent first. For example if the A3LA-
RS were to send the word “hello” encoded in ASCII to the DTE the binary
stream would be hex 00 05 68 65 6c 6c 6f 02 14.
o
If there is no mobile terminated SBD message waiting to be retrieved from the
A3LA-RS, the message length and checksum fields will be zero.
The mobile terminated message buffer will be empty upon power-up.