User manual for the Yinerda Air202GprsDTU module covering hardware, connections, firmware upgrade and AT command usage.
The Air202GprsDTU manual provides detailed information for embedded, development and test engineers on the hardware specifications, pin definitions, and mechanical dimensions of the module. It also describes recommended power supply conditions and operating temperature ranges.
The guide walks users through hardware connections (TTL UART, RS485, SIM card), required tools, the standard internet connection flow, firmware upgrade procedures, AT‑command testing, secondary development resources, and configuration of the standard DTU firmware for network communication. This manual is written in Chinese.
| Communication frequency band | GPRS full band |
|---|---|
| Supported communication protocols | TCP; UDP; HTTP; HTTPS; FTP; MQTT; NTP; SMS; voice call |
| Communication interface | 3.3V TTL UART |
| Maximum UART baud rate | 921600 bps |
| Power supply requirement | 5‑12 V / 1.6 A (stable supply, 2 A recommended) |
| Operating temperature range | -50 °C to 75 °C |
| Module dimensions | 45 mm × 61 mm × 4 mm |
It requires a 5 V to 12 V supply capable of delivering at least 1.6 A; a stable 2 A source is recommended.
Send the AT+CSQ command; a returned value between 17 and 31 indicates acceptable signal quality for stable operation.
Use AT+CSTT="CMNET","","" (or replace CMNET with the carrier‑specific APN).
The module supports UART communication up to 921600 bps.