I. Protocol Packet Format Length Format Description (Byte) Start Bit 2 0x78 0x78（packet length : 1bit）or 0x79x79（packet length 2 bits） Length = Protocol Number + Information Content + Information Serial Number Packet 1(2) + Error Check Protocol Number 1 Transmission packet type（see the following diagram for details） Information The specific contents are determined by the protocol numbers corresponding to N Content different applications. The serial number of the first GPRS data (including status packet and data packet Information Serial 2 and the serial number of data sent such as GPS, LBS) sent after booting is ‘1’, Number later at each time will be automatically added ‘1’. Serial Number (including and Serial “Packet Length” “Information Number”) , Error Check 2 are values of CRC-ITU. CRC error occurs when the received information is calculated, the receiver will ignore and discard the data packet. (See Appendix 1) Stop Bit 2 Fixed value:0x0D0x0A Protocol Number Login Information 0x01 Positioning Data（UTC） 0x22 Heartbeat Packet 0x23 Online Command Response of Terminal 0x21 Alarm Data（UTC） 0x26 GPS Address Inquiry Packet（UTC） 0x2A LBS Address Inquiry Packet 0x17 Online Command 0x80 Time Check Packet 0x8A Information Transmission Packet 0x94
I. Protocol Packet Format Format Description Start Bit 2 0x78 0x78（packet length : 1bit）or 0x79x79（packet length 2 bits） Packet Length 1(2) Length = Protocol Number + Information Content + Information Serial Number + Error Check Protocol Number 1 Transmission packet type（see the following diagram for details） Information Content N The specific contents are determined by the protocol numbers corresponding to different applications. Information Serial Number 2 The serial number of the first GPRS data (including status packet and data packet such as GPS, LBS) sent after booting is ‘1’, and the serial number of data sent later at each time will be automatically added ‘1’. Error Check 2 Serial Number (including “Packet Length” and “Information Serial Number”) , are values of CRC-ITU. CRC error occurs when the received information is calculated, the receiver will ignore and discard the data packet. (See Appendix 1) Stop Bit 2 Fixed value:0x0D0x0A Protocol Number Login Information 0x01 Positioning Data（UTC） 0x22 Heartbeat Packet 0x23 Online Command Response of Terminal 0x21 Alarm Data（UTC） 0x26 GPS Address Inquiry Packet（UTC） 0x2A LBS Address Inquiry Packet 0x17 Online Command 0x80 Time Check Packet 0x8A Information Transmission Packet 0x94 (Byte)