This document introduces AT command overview, types and syntax, as well as GSM Rec. 07.07 standard AT commands, call control commands, and network business commands
The GTM900 AT Command Manual from Huawei describes the complete set of AT commands used to control the GTM900 wireless module. It includes an overview of command types, syntax rules, and detailed descriptions for each command group, helping developers integrate the module into their applications.
The document is organized into sections covering standard GSM AT commands, network service commands, ME control and status commands, extended Huawei‑specific commands, TCP/IP commands, and a comprehensive error‑code list. Each command entry shows the command string, parameters, and expected responses. This manual is written in Chinese.
Use the AT+CGMI command.
Use the %IPCLOSE command with the link number, e.g., %IPCLOSE:
It means username/password registration was rejected, or there is an APN error, card arrears, or the card does not support GPRS.