JT/T808 Protocol

General JT/T808 Protocol

V1.1
JT/T808 Protocol

1. Protocol Basis

1.1 Communication Way

The communication method adopted by the protocol should comply with the relevant

regulations in JT/T 794. The communication protocol adopts TCP, the platform serves

as the server and the terminal serves as the client. The customized or extended part of

the content is marked in bold red in this agreement document.

1.2 Data Type

The data types used in the protocol message are shown in Table 1:

Table 1 Data Type

Data Type Description and requirements

BYTE Unsigned single byte integer ( Byte，8 Digital )

WORD Unsigned double byte integer( Byte，16 Digital)

DWORD Unsigned four-byte integer( Double Byte，32 Digital)

BYTE[n] n byte

BCD[n] 8421 Code，n byte

STRING GBK encoding, using 0 terminator, if there is no data,

put a 0 terminator

1.3 Transmission rules

The protocol uses big-endian network byte order to transfer words and double words.
JT/T808 Protocol

The agreement is as follows:

—— Byte (BYTE) transmission convention: according to byte stream transmission;

——The transmission convention of WORD: first transfer the high eight bits, and then

transfer the low eight bits;

— — The transmission convention of DWORD: first transfer the high 24 bits, then

transfer the high 16 bits, then transfer the high eight bits, and finally transfer the low

eight bits.

1.4 The composition of the message

1.4.1 Message Structure

Each message consists of identification bits, message header, message body and check

code. The message structure diagram is shown in Figure 1:

identificati message message body check code identificati

on bits header on bits

Figure 1 Message Structure

1.4.2 Identification Bits

Using Ox7e means that if 0x7e appears in the check code, message header, and

message body, it must be escaped. The escape rules are defined as follows:

0x7e<——>0x7d is followed by a 0x02;

0x7d<——>0x7d is followed by a 0x01;

The escaping process is as follows:

When sending a message: message encapsulation -> calculate and fill in the

check code -> escape;

JT/T808 Protocol

When receiving a message: Escape and restore——>Verify check code—

—>Analyze the message.

Example:

Send a data packet whose content is 0x30 0x7e 0x08 0x7d 0x55, and the package is

as follows: 0x7e 0x30 7d 0x02 0x08 0x7d 0x01 0x55 0x7e.

1.4.3 Message Header

The content of the message header is shown in Table 2:
Table 2

Start byte Number Field Data Type Description & Requirements

0 Message ID WORD

2 Message WORD The structure diagram of the message

body body attribute format is shown in

attributes Figure 2

4 Terminal BCD[6] This field is the terminal device number

phone affixed to the shell of the device, a total

number of 11 digits, and the device number is

uploaded with 0 in front of it. For

example: 138081234567, data upload

0138081234567

10 Message WORD Cyclically accumulate from 0 in the

serial number sending order

12 Message If the relevant flag in the message body

package attribute determines that the message

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encapsulation is subpackaged, then this item has

item content, otherwise there is no item

The structure diagram of the message body attribute format is shown in Figure 2:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Reserve Subc Data Message body length

ontr encryption

act method

Data encryption method:

—— bit10-bit12 is the data encryption identification bit；

——When these three bits are all 0, it means that the message body is not

encrypted;

——When the 10th bit is 1, it means that the message body is encrypted by RSA

algorithm；

——Other reservations.

Subcontract:

When the 13th bit in the message body attribute is 1, it means that the message

body is a long message, and the packet is sent. The specific subpackage information is

determined by the message package encapsulation item; if the 13th bit is 0, there is no

message package encapsulation in the message header Item field.

The contents of the message package encapsulation items are shown in Table 3

Table 3
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Start Number Data Type Description & Requirements

Byte Field

0 Total WORD The total number of packets after the

number of message is subpackaged

message

packs

2 Packet WORD Start from 1

sequence

number

1.4.4 Check code

The check code refers to the XOR from the beginning of the message to the next

byte until the previous byte of the check code, which occupies one byte.

2. Data Format

2.1 Terminal general response【0001】

Message ID: 0x0001。

The data format of the terminal general response message body is shown in Table 4.

Start Number Data Description & Requirements

Byte Field Type

0 Reply serial WORD The serial number of the corresponding

number platform message

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2 Reply ID WORD The ID of the corresponding platform

message

4 Result BYTE 0：Success/confirmation；1：Fail；2：

Error；

3：not support

2.2 Platform general response【8001】

Message ID：0X8001。

The data format of the platform general response message body is shown in Table 5.

Start Number Data Description & Requirements

Byte Field Type

0 Reply serial WORD The serial number of the corresponding

number terminal message

2 Reply ID WORD The ID of the corresponding terminal

message

4 Result BYTE 0：Success/confirmation；1：Fail；2：

Error；

3：not support 4：Alarm processing

confirmation

2.3 Terminal heartbeat【0002】

Message ID：0X0002.

The terminal heartbeat data message body is empty.

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The platform replies to a general response

2.4 Terminal registration【0100】

Message ID：0X0100。

The data format of the terminal registration message body is shown in Table 6.

Start Number Data Description & Requirements

Byte Field Type

0 State ID WORD Indicate the province where the vehicle

is installed on the terminal, 0 is

reserved, and the default value is taken

by the platform. The provincial ID

adopts the first two of the six

administrative division codes specified

in GB/T 2260.

2 City ID WORD Indicate the city and county where the

vehicle is installed on the terminal, 0 is

reserved, and the platform takes the

default value. The city/county area ID

adopts the six last four digits of the

administrative division code specified in

GB/T 2260.

4 Manufactur BYTE[5] Five bytes, terminal manufacturer code.

er ID
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9 Terminal BYTE[8] Eight bytes, this terminal model is

Model defined by the manufacturer, the

number of digits is not eight, and the

space is filled.

17 Terminal ID BYTE[7] Seven bytes, composed of uppercase

letters and numbers, this terminal ID is

defined by the manufacturer.

21 Color of Car BYTE The color of the license plate, in

Plate accordance with 5.4.12 of JT/T 415-2006,

the value is 0 when it is not on the

license plate

25 Car Plate STRING Motor vehicle license plate issued by

the public security traffic management

department

2.5 Terminal registration response【8100】

Message ID：0x8100。

The data format of the terminal registration response message body is shown in Table 7.

Start Number Data Description & Requirements

Byte Field Type

0 Reply serial WORD The serial number of the corresponding

number terminal registration message

2 Result BYTE 0：Success；1：Vehicle has been

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registered；2：No such vehicle in the

database；3：The terminal has been

registered；4：No such terminal in the

database

3 Authenticati STRING This field is only available after success

on code

The terminal will go through the registration process again every time it is reset, and

the platform needs to respond to the registration message at any time.

2.7 Terminal authentication【0102】

Message ID：0x0102.

The data format of the terminal authentication message body is shown in Table 8-1.

Start Number Data Description & Requirements

Byte Filed Type

0 Authenticati STRING Report the authentication code after the

on code terminal reconnects

Table 8-2 Platform response terminal authentication message body data format

Start Number Data Description & Requirements

Byte Field Type

0 Reply serial WORD The serial number of the corresponding

number terminal message

2 Reply ID WORD 0x0102:Terminal authentication

message ID
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4 Result BYTE 0：Success/confirmation；1：Fail

2.8 Set terminal parameters【8103】

Message ID：0x8103

The data format of the message body for setting terminal parameters is shown in Table 9.

Start Byte Number Field Data Type Description &

Requirements

0 Total number of BYTE

parameters

1 List of parameter The parameter

items item format is

shown in Table 10

Table 10 Data format of terminal parameter item

Number Field Data Type 描述及要求

Parameter ID DWORD Parameter ID definition and

description are shown in Table 11

Parameter BYTE

Length

Parameter If it is a multi-value parameter,

value multiple parameter items with the

same ID are used in the message, such

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as the telephone number of the

dispatch center

Table 11: Definition and description of each parameter item of terminal parameter setting

Paramete Data Type Description & Requirements

r ID

0x0001 DWORD Terminal heartbeat sending interval, in seconds(s)

0x0010 STRING Main server APN, wireless communication dial-up

access point.

0x0013 STRING Main server address, IP or domain name

0x0017 STRING Backup server address, IP or domain name

0x0018 DWORD Server TCP port

0x0020 DWORD Location report strategy, 0: regular report; 1: fixed

distance report; 2: regular and fixed distance report

0x0027 DWORD Reporting time interval during sleep, in seconds

(s), >0

0x0029 DWORD The default time reporting interval, in seconds (s), >0

0x002C DWORD The default distance report interval, the unit is meter

(m),>0

0x0030 DWORD Inflection point supplementary transmission angle,

<180°

0x0055 DWORD Maximum speed in kilometers per hour (km/h)

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0x0056 DWORD Overspeed duration in seconds (s)

0x0080 DWORD Vehicle odometer reading, 1/10km

0x0081 DWORD Province ID where the vehicle is located

0x0082 DWORD City ID where the vehicle is located

0x0083 STRING Motor vehicle license plate issued by the public

security traffic management department

0x0084 BYTE The color of the license plate is in accordance with

5.4.12 of JT/T415-2006

2.9 Query terminal parameters【8104】

Message ID：0x8104

The query terminal parameter message body is empty.

2.10 Query terminal parameter response【0104】

Message ID：0x0104。

The data format of the query terminal parameter response message body is shown in Table 12.

Start Byte Number Filed Data Description & Requirements

Type

0 Reply serial WORD The serial number of the

number corresponding terminal parameter

query message

2 Number of BYTE

response
JT/T808 Protocol

parameters

3 List of The parameter format and definition

parameter are shown in Table 10

items

2.11 Terminal control【8105】

Message ID：0x 8105。

The data format of the terminal control message body is shown in Table 13.

Table 13 Terminal control message body data format

Start Number Field Data Description & Requirements

Byte Type

0 Command BYTE See Table 14 for the description of

word terminal control command words

1 Command STRING The command parameter format is

parameters described later. Each field is

separated by a half-width ";", and

each STRING field is processed

according to GBK encoding before

forming a message

Table 14 Description of terminal control command words

Comm Command Description & Requirement

JT/T808 Protocol

and Parameter

Byte

0x04 No Terminal reset (restart)

0x05 No Restore the factory settings of the terminal

0x17 No Turn on voice recording

0x18 2 Bytes Turn on continuous recording

Recording time, in minutes

0x19 No Stop all recording

0x64 No Cut off oil and electricity

0x65 No Restore oil and electricity

0x66 No External fortification

0x67 No External disarm

2.12 Location information report【0200】

Message ID：0x0200。

The location information report message body consists of a list of location basic

information and location additional information items. The message structure diagram

is shown in Figure 3:

Basic location information List of location additional information

items

The location additional information item list is composed of various location

JT/T808 Protocol

additional information items, or not, and is determined according to the length field in

the message header.

The data format of basic position information is shown in Table 16.

Start Number Field Data Description & Requirements

Byte Type

0 Alarm sign DWORD Refer to Table 18 for the definition of

alarm flag bit

1 Status DWORD The status bit definition is shown in

Table 17

8 latitude DWORD The latitude value in degrees is

multiplied by 10 to the 6th power,

accurate to one millionth of a degree

12 longitude DWORD The latitude value in degrees is

multiplied by 10 to the 6th power,

accurate to one millionth of a degree

16 Height WORD Altitude above sea level, in meters

(m)

18 Speed WORD 1/10km/h

20 Direction WORD 0-359, true north is 0, clockwise

21 Time BCD[6] YY-MM-DD-hh-mm-ss(GMT+8 time,

the time involved after this standard

adopts this time zone)

JT/T808 Protocol

Table 17 Status bit definition

Bit Status

0 0: ACC Off；1:ACC On

1 0: Un-Position；1: Positioned

2 0: north latitude；1: south latitude

3 0: East longitude；1: West longitude

4-5 Reserve

6 0: Disarm 1：Fortify

7-9 Reserve

10 Oil circuit status：0: normal；1: Disconnected

11 Power-off state：0: Main Power Normal:1: Main Power

Disconnected

12-31 Reserve
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Table 18 Definition of alarm flag bit

Bit Definition Processing instructions

0 1:Emergency alarm (SOS alarm) Cleared after receiving the response

1 1：Overspeed Alarm The flag is maintained until the

alarm condition is removed

2 1：Fatigue driving The flag is maintained until the

alarm condition is removed

3-6 Reserve

7 1：Terminal main power supply The flag is maintained until the

undervoltage alarm condition is removed

8 1：Main power disconnection The flag is maintained until the

alarm alarm condition is removed

9-14 Reserve

15 Low battery alarm (wireless Cleared after receiving the response

device)

16 Vibration Alarm Cleared after receiving the response

17-18 Reserve

19 1：Overtime parking The flag is maintained until the

alarm condition is removed

20-27 Reserve

28 1：Illegal vehicle displacement Cleared after receiving the response

29~31 Reserve
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See Table 19 for the format of location additional information items.

Table 19 Location Additional Information Item Format

Number Field Data Type Description &

Requirements

Additional Information BYTE 1-255

ID

Additional Information BYTE

Length

Additional Information Additional information

is defined in Table 20

Table 20 Definition of additional information

Additional Additional Description & Requirements

Information Information Length

ID

0x01 4 Mileage, DWORD, 1/10km, local

accumulated mileage of the terminal

0x2B 4 The two-channel fuel consumption data

adopts the reported data as the Changrun

fuel consumption protocol data

0x30 1 Network signal strength CSQ value 0-31

0x31 1 The number of GPS satellites, the signal

value is greater than 25dB The number of

JT/T808 Protocol

satellites

0x51 16 16 bytes, 2 bytes for a group temperature,

a total of 8 channels of temperature

0x52 1 Forward and reverse (0: unknown; 1:

forward (empty) 2: reverse (heavy); 3:

stop)

0x53 1+n*8 2G base station data

0x53 1+n*8 Base station data: The first

byte is the number of base stations,

followed by n base station data;

Base station data: 0-1 MCC;

2 MNC; 3-4 LAC; 5-6 CELLID; 6 signal

strength

0x54 1+n*7 Wifi data: the number of wifi in the first

byte, followed by n wifi data; WIFI data:

0-5 wifiMac; 6 signal strength

0x56 2 Internal battery level

Byte 1, power level 0-10

Byte 2, reserved

0x5D 1+n*10 4G base station data

The first byte is the number of base

stations, followed by n base station data;

JT/T808 Protocol

0x5D 1+n*10 Base station data: 0-1 MCC; 2

MNC; 3-4 LAC; 5-8 CELLID; 9 signal

strength

0x61 2 Main power supply voltage value, unit

0.01V

0xF1 20 ICCID, the terminal will report once every

time the terminal completes the platform

authentication.

0xF3 1 Armed/disarmed state, 0x00 is disarmed,

0x01 is armed

2.13 Location information query【8201】

Message ID: 0x8201。

The location information query message body is empty.

2.14 Location information query response【0201】

Message ID: 0x0201。

The data format of the location information query response message body is

shown in Table 24.

Table 24: Data format of location information query response message body

Start Byte Number Field Data Type Description &

Requirements

0 Reply serial number WORD The serial number

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of the

corresponding

location

information query

message

2 Location For location

information report information report,

see 8.12

2.16 Bulk upload of positioning data (refill data)【0704】

See Table 26 for the data format of the message body of the positioning data bulk

upload.

Table 26 The data format of the message body of the positioning data bulk upload

Start Byte Number Field Data Type Description & Requirements

0 Number of WORD The number of location report

data items data items included, >0

1 Location data BYTE 0: Normal position batch report;

type 1: Blind spot supplementary

report

2 Location For definition, see Table 27 of

report data Location Report Data Item

item
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Table 27 Data format of location report data item

Start Byte Number Field Data Type Description & Requirements

0 Location WORD Position data body length, n

report data

length

2 Location BYTE[n] Report in the same position in

report data format, see 2.13 for definition

body

2.17 Text information issuance【8300】

Message ID: 0x8300。

The data format of the message body sent by the text information is shown in

Table 28.

Table 28 Data format of the message body sent by the text information

Start Byte Number Data Type Description & Requirements

Field

0 Sign BYTE The text information flag bit [fixed

to 0x02] see Table 29 for the

meaning

1 Text STRING The maximum length is 1024

Informat bytes, encoded by GBK

ion
JT/T808 Protocol

Table 29 Meaning of text information flags

Bit Sign

0 1：Emergency

1 Reserve

2 1：Transparent transmission of text

3 1：Terminal TTS broadcast

4 1：Advertising screen display

5-7 Reserve

2.18 Report text information【6006】

Message ID: 0x6006。

The data format of the text information report message body is shown in Table 30.

(8300 issued by the platform, 6006 answered by the terminal)

Table 30: Text information report message body data format

Start Byte Number Field Data Type Description & Requirements

0 Sign BYTE Fixed as 0x00

1 Text STRING The maximum length is

Information 1024 bytes, encoded by GBK

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2.19 Recording related

The recording format currently uses the AMR file format, voice control and

continuous recording control through the 0x8105 command.

Multimedia data upload

Message ID: 0x0801。

The data format of the multimedia data upload message body is shown in the table

below.

Start Byte Number Data Type Description & Requirements

Field

0 Multimedi DWORD >0

a ID

4 Multimedi BYTE 0: image; 1: audio; 2: video

a Type

5 Multimedi BYTE 0: JPEG; 1: TIF; 2: MP3; 3: WAV; 4: WMV;

a format other reserved

encoding

6 Event item BYTE 0: Command issued by the platform; 1:

coding Timed action; 2: Robbery alarm triggered; 3:

Collision rollover alarm triggered; other

reserved

7 Channel ID BYTE
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8 Multimedi

a data

packet

Only the first data packet contains the 8 bytes of "Multimedia ID — Channel ID", the

subsequent packets are directly multimedia data, and each packet carries a maximum

of 1000 bytes of multimedia data, and the last packet is subject to the actual file.

The platform uses a general response to reply to each multimedia data packet.

Multimedia data upload result

Message ID: Ox8800。

The data format of the multimedia data upload response message body is shown

in the table below.

Start Number Field Data Type Description & Requirements

Byte

0 Multimedia DWORD >0

ID

4 Total number BYTE

of

retransmitted

packets

5 Retransmissio No more than 125 items, no such field

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n packet ID means that all data packets have been

list received

After the platform has processed all media packages, it needs to send this message to

the terminal to report that the file has been received or the corresponding package

needs to be retransmitted.

If the terminal does not receive this message within 5 seconds, it will automatically exit

the current file upload process.