1.The structure of commands send by terminal:

Normal information(v1):

*XX,YYYYYYYYYY,V1,HHMMSS,S,latitude,D,longitude,G,speed,direction,DDMMYY,vehicle_status#

Confirmation of information(V4):

*XX,YYYYYYYYYY,V4,CMD,hhmmss,HHMMSS,S,latitude,D,longitude,G,speed,direction,DDMMYY,vehicle_status#

In which:
* : Head of command
XX : Name of maker, Consists of two ASCII characters, such as HQ.
, : separator
YYYYYYYYYY : SN of terminal, is ten characters front of IMEI.
CMD : Command
HHMMSS : Time: hour/minute/second,device time, GMT, Beijing is 8 hours ahead GMT.

S : Effective mark of data, ‘A’ stand for effective, ‘V’ stand for invalid.
Latitude : Latitude, format : DDFF.FFFF, DD : Degree（00 ~ 90）, FF.FFFF : minute
(00.0000 ~ 59.9999), keep four decimal places.
D : latitude marks (N:north, S:south)
Longitude : longitude, format : DDDFF.FFFF, DDD : Degree（000 ~ 180）, FF.FFFF : minute
(00.0000 ~ 59.9999), keep four decimal places.
G : longitude marks (E:east, W:west)
Speed: speed,range of 000.00 ~ 999.99 knots, Keep two decimal places.
Speed maybe empty, as longitude,G,,direction, speed is 0.
Direction: Azimuth, north to 0 degrees, resolution 1 degrees, clockwise direction.
Direction maybe empty, as longitude,G,speed,, MMDDYY, azimuth is zero.

DDMMYY:day/month/year

vehicle_status(V1): Vehicle state, four bytes, says the terminal parts state, vehicle parts state and alarm state, etc. Use ASCII character and hexadecimal values. Below are the meaning of each byte, use negative logic, bit=0 is effective. The table below:

Wire vehicle tracker

Wireless vehicle tracker

Pet&personal tracker

2.Commands send by center

1)Clear alarm R7
*XX,YYYYYYYYYY,R7,HHMMSS #

For example: *TH, 000000,R7,130305#
Terminal received the command will clear all the alarm information, but does not send back information, monitoring system can be appended to send a single monitoring command to confirm whether have clear alarm or not.

3.GPRS agreement

Standard mode(Binary V1 normal information) encoding format：

In which, “$”(0x24): Recording Head, for the start point of center identity record;

Time: 0x050316, GMT+0 5 o’clock 3 minutes 16 seconds, same as Beijing time(GMT+8) 13 o’clock 3 minutes 16 seconds;

Date: 0x220902, 22th September,2002;

Latitude value: 0x22128745,22°12.8745;

Longitude value: 0x113466574C,113°46.6574,meaning of last bit(No.0x15):

      bit7654，last place of longitude;

                bit3，1：east longitude,0：west longitude;

      bit2，1：north latitude,0：south latitude;

      bit1，1：A，0：V

                bit0, not defined

Speed, direction：0x014028:speed 014 knot，direction 028;

vehicle_status、 User_alarm_flag：Vehicle status in binary system, and user defined alarm status,same meaning as SMS(in ASCII).

Operators number:Recording numbers in binary system, add 1 every time send back record data.

Encoding format:

Base station information

Country code, 460 = 0x01CC

Operator number, 01 = 0x01

Station number, 34569 = 0x8763

Cell ID, 23452 = 0x5B9C

Hexadecimal data flow:  01 CC 01 87 63 5B 9C

Multi cell base station protocol

*XX,YYYYYYYYYY,NBR,HHMMSS,MCC,MNC,TA,NUM,LAC,CID,RXLEV ,LAC,CID,RXLEV….,DDMMYY,vehicle_status#

    XX：Manufacturer

    YYYYYYYYYY：ID

        HHMMSS time

    MCC  Country Code MCC(3 bits)

    MNC  Network code MNC(3 bits)

NUM  Numbers of Base Station, maximum is 6.

TA    GSM time delay

    LAC Location Area Code LAC(5 bits)

    CID Cell Tower CID(5 bits)

    RXLEV Signal Strength

    DDMMYY Date

    vehicle_status  （refer to “Common Data Definition”）

E.g.

*HQ,7893267560,NBR,081606,460,0,1,4,9338,3692,150,9338,3691,145,9338,3690,140, 9338,3692,139,220513,FFFFFBFF#

Multi cell base station protocol,add Last field of ASCII  power level information:

*HQ,7893267560,NBR,081606,460,0,1,4,9338,3692,150,9338,3691,145,9338,3690,140, 9338,3692,139,220513,FFFFFBFF,cell#

Cell value 1-6 (1-10%,2-20%,3-40%,4-60%,5-80%,6-100%)

Time calibration protocol in center for long standby time terminals:

Server receive V1 and NBR command, then reply with V4, time calibration as GMT+0 time.
//*HQ,8856000065,V4,NBR,20150525102030#
//*HQ,0600097800,V4,V1,20150525102030#

20150525102030 It is GMT+0 2015-05-25 10 o’clock 20 minutes 30 seconds GMT+8 18 o’clock 20 minutes 30 seconds