AVL GPRS Data Protocol
This is the AVL GPRS data format communication protocol, this protocol is defined to make
available a datagram mode of packet communication, it provides a procedure for application
programs to send messages to other device.
Command Format Specification
Note: All multi-byte data is based on high-byte first, low-byte after for organization in this
protocol.
The data received format in the Server is as below:
The data of the device send to the server:
Format:$$(2 Bytes) + Len(2 Bytes) + IMEI(15 Bytes) + | + AlarmType(2 Bytes) + GPRMC + | +
PDOP + | + HDOP + | + VDOP + | + Status(12 Bytes) + | + RTC(14 Bytes) + | + Voltage(8 Bytes)
+ | + ADC(8 Bytes) + | + LACCI(8 Bytes) + | + Temperature(4 Bytes) | + Mile-meter(14 Bytes)+ |
Serial(4 Bytes) + | + Checksum (4 Byte) + rn(2 Bytes)
The format of ASCII:
$$B0353358019462410|AA$GPRMC, 102156.000, A, 2232.4690, N, 11403.6847, E, 0.00, , 180909, , *1
5|02.0|01.2|01.6|000000001010|20090918102156|14181353|00000000|279311AA|0000|0.7
614|0080|D2B5
Code                                          Explanation
$$                        2Bytes, indicates header of command from tracker unit to call centre, in ASCII
                                    code (hex is 0x24).
Len                     2Bytes, indicates length of all command, including header and end (the array is
                                     first high to low).
IMEI                     15Bytes, at most 20 bytes.
Alarm type           2Bytes, the GPRS data trigger type.
DATA                    GPRMC string
                               PDOP
                               HDOP
                               VDOP
                               Status (12bytes)
                                RTC (14bytes)
                                Voltage(8bytes)

ADC                  8bytes, the ADC value.
LACCI               Location information elements
Temperature    Temperature information
Milemeter          Mileage data
Serial ID           4bytes, sign every GPRS data, the range is [0001-9999], then                             circle it again from 0001 to 9999.
Checksum       4Bytes, means CRC check of all the data ahead, CRC-16 modbus (Polynomial =
0xA001, initialize data is 0xffff) checksum, not including its own byte and end
characters. For example:
$$B0353358019462410|AA$GPRMC, 102156.000, A, 2232.4690, N, 11403.6847, E,
0.00, , 180909, , *15|02.0|01.2|01.6|000000001010|20090918102156|1418135
3|00000000|279311A A|0000|0.7614|0080|D2B5
            D2B5= CRC-16 modbus
($$B0353358019462410|AA$GPRMC, 102156.000, A, 2232.4690, N, 11403.6847,
E, 0.00, , 180909, , *15|02.0|01.2|01.6|000000001010|20090918102156|14181
353|00000000|279311AA|0000|0.7614|0080|).
rn 2Bytes, end char (hex format is 0x0d, 0x0a).

• Alarm type
o 0x01 SOS button is pressed
o 0x49 Button A is pressed
o 0x09 Auto ShutdownAlarm
o 0x10 Low battery Alarm
o 0x11 Over Speed Alarm
o 0x13 Recover From Over Speed
o 0x30 Parking Alarm
o 0x42 Out Geo-fence Alarm
o 0x43 Into Geo-fence Alarm
o 0x50 IO-1 Close
o 0x51 IO-1 Open
o 0x52 IO-2 Close
o 0x53 IO-2 Open
o 0x54 IO-3 Close
o 0x55 IO-3 Open
o 0x56 IO-4 Close
o 0x57 IO-4 Open
o 0x60 Begin Charge
ADC 8bytes, the ADC value.
LACCI Location information elements
Temperature Temperature information
Milemeter Mileage data
Serial ID 4bytes, sign every GPRS data, the range is [0001-9999], then circle it again from
0001 to 9999.
Checksum 4Bytes, means CRC check of all the data ahead, CRC-16 modbus (Polynomial =
0xA001, initialize data is 0xffff) checksum, not including its own byte and end
characters. For example:
$$B0353358019462410|AA$GPRMC, 102156.000, A, 2232.4690, N, 11403.6847, E,
0.00, , 180909, , *15|02.0|01.2|01.6|000000001010|20090918102156|1418135
3|00000000|279311A A|0000|0.7614|0080|D2B5
D2B5= CRC-16 modbus
($$B0353358019462410|AA$GPRMC, 102156.000, A, 2232.4690, N, 11403.6847,
E, 0.00, , 180909, , *15|02.0|01.2|01.6|000000001010|20090918102156|14181
353|00000000|279311AA|0000|0.7614|0080|).
rn 2Bytes, end char (hex format is 0x0d, 0x0a).
o 0x61 End Charge
o 0x88 Heartbeat
o 0x91 Into Sleep Mode
o 0x92 Wakeup From Sleep Mode
o 0xAA Interval GPRS data
• Status(12 Bytes) —— Status:
o Byte 01 —— SOS button
o Byte 02 —— Button A button
o Byte 03 —— Switch Input 1
o Byte 04 —— Switch Input 2
o Byte 05 —— Digital Input 1
o Byte 06 —— Digital Input 2
o Byte 07 —— Digital Input 3(reserve)
o Byte 08 —— Digital Input 4(reserve)
o Byte 09 —— Digital outputA
o Byte 10 —— Digital outputB
o Byte 11 —— Digital outputC
o Byte 12 —— Out 4(reserve)
• Voltage(8 Bytes) ——Value of the voltage:
o Format:ABBBIIII
o A —— Charge Status (0 = Off Charge , 1 = On Charge)
o BBB —— Battery Voltage (For example, 367 mean 3.67V)
o IIII —— Input Charge Voltage (For example, 1251 mean 12.51V)
• ADC(8 Bytes) —— AD collection:
o Format:CCCCDDDD
o CCCC —— ADC0 collect (For example, 1251 mean 12.51V)
o DDDD —— ADC1 collect (For example, 1251 mean 12.51V)(reserve)
• LACCI(8 Bytes) —— Location information elements:
o Format:LLLLCCCC
o LLLL —— Location area code
o CCCC —— Cell ID
• Temperature(4 Bytes) —— Temperature(reserve for the device has no temperature
sensor):
o Format:STTT
o Precision is 0.1℃
o The first byte “S” mean sign, such as“0/1/-”
o Eg:0345 mean +34.5℃, 1234 mean +123.4℃, -123 mean -12.3℃
• Mile-meter(14 Bytes) —— Location information elements:
o Format is AAAA.BBBBKm.
o Four bytes after the radix point.
• Serial(4 Bytes) —— Serial number:
o Format:SSSS
o Every time reboot the device or reset, the serial number will initialize to 0001.
o Every GPRS message send out will add one
o After the serial number to 9999, restart from 0001 again