OTA (Over-The-Air) Packet
OTA Packet structure
| Header | ||||
|---|---|---|---|---|
| Field | Size (bits) | Bit Range | Description | Breakdown |
| Start byte | 8 | 0–7 | Starting character $ (ASCII value 36) | $ |
| Data length | 12 | 8–18 | 2-byte length of the data following the header | |
| Num of data packets | 5 | 19–23 | Number of packets (0–32) | 0 - 32 |
| IMEI | 50 | 24–74 | Unique device identifier | Integer type: e.g., 887744556677882 |
| Packet Type | 5 | 75–79 | Type of packet |
00 - Device info 01 - Alert packet 02 - OTA pkt 03 - ErrorPacket 04 - Device configuration packet 05 - IP configuration packet |
| Data | ||||
| OTA Source | 5 | — | Source of OTA |
00 - OTA_SRC_SERIAL 01 - OTA_SRC_SMS 02 - OTA_SRC_IP_TRANSIGHT 03 - OTA_SRC_IP_CUSTOMER |
| Error status | 8 | — | Non-zero value indicates an error | NO ERROR = 0, ERROR = Non-zero value |
| Cell Number | 51 | — |
First bit (MSB) with value 1 = number includes country code. If MSB = 0, number is without country code. Remaining 50 bits represent mobile number in integer format. || Example: 400D6276ACF52 (+919784312658) | |
| Date & Time | 32 | — | UTC Timestamp | UTC time in seconds |
| Timezone | 8 | — |
Timezone in quarter-hours (e.g., 22 = +5:30) Quarter-hour increment = 15 minutes per unit Range: -48 to 56 (2’s complement for negative) || Example: 22 = 22 × 15 = 330 mins 330 ÷ 60 = 5.5 hrs = +5 hours 30 mins ahead of UTC | |
| Command Length | 8 | — | Length of command string | |
| Command | max 600 bits (75 bytes) | — | Input command with arguments, char array, terminated with null character |
Example: SET CUIOCFG:IO1-DI-IGN*IO2_AN_GEN*IO3-DI-PBN*IO4-DO-IMB* |
| Response Length | 8 | — | Length of response string | |
| Response | max 512 bits (64 bytes) | — | Response for particular command |
Example: IOCFG:IO1-DI-IGN*IO2-AN_GEN*IO3-DI-PBN*IO4-DO-IMB* |
| Tail | ||||
| End Character | 8 | 0–7 | Starting character * (ASCII value 42) | * |
| CRC | 8 | Aug-15 |
8-bit XOR CRC of data starting from $ to * (excluding $ and *) || | |
Sample Packet
{"HEX": "240340e1cabd09208ca210000000000000006824646f160947455420545355524c1c55524c3a5443503a3134312e3134372e3132382e3135303a383738382aa2",
"cell_no": 0,
"command": "GET TSURL",
"command_length": 9,
"dateTime": 1747215471,
"dateTime_tz": "2025-05-14 15:07:51.000",
"error_status": 0,
"imei": 860187062240357,
"insert_time": "Wed, 14 May 2025 09:38:03 GMT",
"ota_source": 2,
"packetType": 2,
"response": "URL:TCP:141.147.128.150:8788",
"response_length": 28,
"send_time": "2025-05-14 15:07:51",
"timezone": 22}