| A | B | C | D | |
|---|---|---|---|---|
1 | ||||
2 | ||||
3 | Bi-directional communication protocol: device -> server, server -> device. | |||
4 | ||||
5 | Each parcel (PACKAGE) from the device requires confirmation from the server (SERVER_COM) | |||
6 | ||||
7 | If there is no confirmation from the server, the device will duplicate packet until confirmation. | |||
8 | ||||
9 | Data transmission to the server is in continuous TCP session (GPRS). | |||
10 | ||||
11 | Data are transmitted in binary form, byte order little-endian. | |||
12 | ||||
13 | ||||
14 | The structure and procedure packs | |||
15 | ORDER OF TRANSMISSION | DEVICE >> | << SERVER | |
16 | first connection with the server transmitted HEADER - in response to confirmation HEADER further PACKAGE + SERVER_COM (confirmation) | |||
17 | HEADER | |||
18 | SERVER_COM | |||
19 | PACKAGE | |||
20 | PACKET_0 | |||
21 | ...... | |||
22 | PACKET_N | |||
23 | SERVER_COM | |||
24 | subsequent packets PACKAGE + SERVER_COM (confirmation) | |||
25 | ||||
26 | PACKAGE | |||
27 | PACKET_0 | |||
28 | ..... | |||
29 | PACKET_N | |||
30 | SERVER_COM | |||
31 | ||||
32 | asynchronous command Only a command (between packages PACKAGE) | SERVER_COM | ||