Page 58
SmartOne C User Manual
Confidential & Proprietary Information
9100-0410-01 R2.4
SEND TRUNCATED MESSAGE (SERIAL MESSAGE TYPE 0X26)
The SmartOne will perform a GPS location and append user data passed to the unit via the Truncated Message
command 0x26.
47 bytes plus 6 bits of user data may be sent with the standard GPS location information in a messaging
burst. Two bits are set in the on-air message by the SmartOne informing the recipient that the message is the
Truncated type.,The following table defines the message structure of the “data” portion of the command used
to send a Truncated message.
Communication to the SmartOne will follow the following specific format:
Example 1 - Sending a “Truncated” User Message
The host sends:
AA 08 26 10 22 33 <CRC-low> <CRC-High>
The SmartOne would respond:
AA 05 26 <CRC-Low> <CRC-High>
What would go out over the air is:
11 Lat-3 Lat-2 Lat-1 Lon-3 Lon-2 Lon-1 22 33
NOTE:
The least two significant bits of the first byte are always “01” for a truncated message, the
remaining 6 bits make up the top 6 bits of the first byte sent in the serial command, in this example
000100xx (with the “xx” representing the two bits that the SmartOne forces to “01”).
The 22 and the 33 that the user sent are appended after the 6 bytes of latitude and longitude.
Example 2 - Using a Longer Message
The host sends:
AA 0D 26 10 22 33 44 55 66 77 88 <CRC-low> <CRC-High>
NOTE:
The length field: 0D – 0D is the number 13 in hexadecimal, the length of the total serial command.
The SmartOne would respond:
AA 05 26 <CRC-Low> <CRC-High>
What would go out over the air is:
11 Lat-3 Lat-2 Lat-1 Lon-3 Lon-2 Lon-1 22 33 44 55 66 77 88 00 00 00 00
NOTE:
All on air messages are padded to a multiple of 9 bytes. This is the reason for the trailing zeros in
this example.
BYTE
BIT
PARAMETER
DESCRIPTION
DEFAULT VALUE
0
7.2
SUBMASK BITS
User data bits. Bits 1:0 are reserved and will be
masked by SmartOne
0X00
VARIABLE
USER DATA
Supports a maximum of 47 total bytes in this field.
User application (smart sensor) should transmit only as
many bytes as needed (don’t pad the message) in order
to keep on air packets to a minimum
