Need help?Do you have a question about the Quectel GSM/GPRS Module Series and is the answer not in the manual?
Details the revision history of the document, including dates and changes made.
Provides a summary of key AT commands for GSM QuecCell functionality, listing commands and their purposes.
Explains the AT+QOPS command for scanning GSM base station information and network details.
Details the AT+QENG command for enabling/disabling engineering mode and reporting network information.
Explains the AT+QLOCKF command to lock a specified base station or ARFCN.
Details the AT+QCHINFO command for obtaining detailed network channel information.
Describes the AT+QLASTTA command to retrieve the last valid Time Advance value.
Explains the AT+QFORBIDMNC command to forbid specific operators and radio bands.
Details the AT+QSCANF command for scanning ARFCN receiving levels across different bands.
Provides practical examples of using the AT+QOPS command for base station scanning and information retrieval.
Shows example usage scenarios for the AT+QENG command in engineering mode for network monitoring.
Demonstrates examples of how to lock a base station or specific ARFCNs using the AT+QLOCKF command.
Provides example scenarios for retrieving detailed channel information with the AT+QCHINFO command.
Shows examples of obtaining the last valid Time Advance value using the AT+QLASTTA command.
Illustrates examples of forbidding operators and radio bands using the AT+QFORBIDMNC command.
Presents examples of scanning ARFCN receiving levels across different bands with AT+QSCANF.
The Quectel GSM QuecCell module is a wireless module designed to provide comprehensive control and information regarding GSM network interactions. It offers a range of AT commands that allow users to scan detailed base station information, lock onto specific GSM frequencies, and forbid specified operators, enabling customers to select their preferred network in a given location. This functionality is embedded directly within Quectel modules, making it a powerful tool for network management and optimization.
The core function of the QuecCell module revolves around its ability to interact deeply with GSM networks. Through its AT commands, it can perform several key operations:
Scanning Basic Station Information (AT+QOPS): This command allows the module to scan all available GSM frequencies and report detailed information about nearby base stations. This includes data such as operator name (long, short, and numeric formats), location area code (LAC), cell ID (CI), base station identity code (BSIC), received signal level (RxLev), and absolute radio frequency channel number (ARFCN). The module can identify available operators, the current operator, and even forbidden operators. This comprehensive scan is crucial for understanding the network landscape in any given area and is capable of operating even without a SIM card inserted, providing flexibility for initial setup or diagnostic purposes. The scan results are indexed, with a maximum of 10 entries per operator, allowing for a detailed overview of the strongest signals.
Engineering Mode (AT+QENG): The Engineering Mode is a diagnostic feature designed for field engineers to monitor and test network information. It provides insights into both the serving cell (the cell the module is currently registered with) and neighboring cells. Users can switch this mode on or off and configure it to display different levels of detail. For instance, it can show only serving cell information, or include information for 1-6 neighboring cells. A more advanced dump option also includes a list of ARFCNs and the cell frequency list (CA) of the serving cell. The reported information includes mobile country code (MCC), mobile network code (MNC), LAC, cell ID, BCCH, BSIC, received signal level in dBm, C1 and C2 values, transmit power maximum access to CCH, receive level access minimum, timeslots, MAIO, HSN, ARFCN of TCH, timing advance (TA), and RX quality (sub and full). When enabled in a specific mode, the module can automatically report URCs (Unsolicited Result Codes) every 5 seconds, providing real-time updates on network conditions. This mode is invaluable for troubleshooting and optimizing network connectivity.
Locking the Base Station (AT+QLOCKF): This command allows the module to lock onto a specified base station. By using information gathered from AT+QOPS or AT+QENG, users can identify a desirable base station and then instruct the module to maintain its connection with that specific station. The command supports locking by mode, band (e.g., 1900 band), and specific ARFCNs. This feature is particularly useful in scenarios where a stable connection to a particular base station is critical, or when avoiding less reliable or undesirable base stations. The module can be configured to enable or disable frequency locking, and the status of the lock can be queried. The band1900 parameter helps distinguish ARFCNs that might overlap between DCS1800 and PCS1900 bands.
Getting Channel Information (AT+QCHINFO): This command reports detailed network information about the serving channel. It can be set to either report automatically or query manually. The information provided includes the radio resource (RR) state (e.g., Null, Inactive, Cell Select, Idle, Access, Packet Transfer, Dedicated, Cell Reselect), ARFCN, received signal level in dBm, channel type, timing advance (TA), and RX quality (sub and full). This command is available when the Engineering Mode (AT+QENG) is active, providing a focused view of the current channel's performance. The TA parameter, in particular, will update when SMS calls or GPRS data is transmitted, indicating active communication.
Getting Last Valid TA Value (AT+QLASTTA): This command retrieves the last valid timing advance (TA) value. The TA value is an important indicator of the distance between the mobile device and the base station. This command is also available when the Engineering Mode (AT+QENG) is active, allowing users to quickly check the TA without needing to parse the full channel information.
Forbidding Operators (AT+QFORBIDMNC): This powerful feature allows the module to forbid specified operators and radio bands. This means the module will not camp on networks belonging to the forbidden operator, even if a SIM card is not inserted. Users can read or write lines of forbidden data, specifying the MCC, MNC, and band. This is useful for controlling network access, preventing roaming onto expensive networks, or ensuring the device connects only to preferred operators. The settings are stored in NVRAM and take effect after the module is rebooted, providing persistent configuration.
Scanning ARFCN Receiving Level (AT+QSCANF): This command scans a specified frequency or band and lists the ARFCNs and their corresponding received signal levels (RxLevel) in descending order of signal strength. This scan is performed when the module's functionality (CFUN) is set to 0 or 4 (indicating disabled phone functions or disabled phone transmitting/receiving RF circuits, respectively). It can list up to 20 channels, providing a clear picture of signal strength across different frequencies. This is particularly useful for identifying the strongest available channels for a given band, aiding in network selection and optimization.
The QuecCell module is designed for flexibility and control in various applications requiring precise network interaction.
Network Selection and Optimization: The ability to scan basic station information (AT+QOPS) and ARFCN receiving levels (AT+QSCANF) allows users to identify the strongest and most reliable networks in a given area. This is crucial for applications where consistent connectivity is paramount, such as remote monitoring, asset tracking, or industrial IoT devices. By understanding the network landscape, users can make informed decisions about which operators and frequencies to prioritize.
Network Locking: The AT+QLOCKF command provides a mechanism to ensure the module stays connected to a specific base station. This can be vital in situations where a particular base station offers better service, lower latency, or is part of a private network. For example, in a fixed wireless application, locking to a known good base station can prevent the module from hopping to a weaker or less desirable one.
Operator Control: The AT+QFORBIDMNC command offers granular control over which operators the module can connect to. This is highly beneficial for managing costs (e.g., preventing accidental roaming), enforcing service agreements, or adhering to specific network policies. The persistence of these settings in NVRAM ensures that the module maintains its forbidden operator list even after power cycles.
Diagnostic and Troubleshooting: The Engineering Mode (AT+QENG) and channel information commands (AT+QCHINFO, AT+QLASTTA) are powerful diagnostic tools. Field engineers can use these commands to monitor real-time network parameters, identify signal strength issues, analyze cell handovers, and troubleshoot connectivity problems. The automatic URC reporting in Engineering Mode provides continuous feedback, which is essential for in-depth analysis.
SIM Card Flexibility: Many of the scanning and network information commands, such as AT+QOPS, can be executed even without a SIM card inserted. This allows for preliminary network assessment and configuration before a SIM card is provisioned, streamlining the deployment process.
While the QuecCell module itself is a hardware component, its AT commands offer features that contribute to the maintenance and long-term reliability of the device's network connectivity.
Persistent Configuration: Settings related to forbidden operators (AT+QFORBIDMNC) are stored in NVRAM, meaning they persist across reboots. This reduces the need for constant reconfiguration and ensures that the module adheres to desired network policies without manual intervention after each power cycle.
Error Reporting: The module provides clear error messages, such as +CME ERROR: <err>, which are crucial for diagnosing issues. The manual includes a summary of +CME ERROR codes, helping users quickly understand the nature of a problem (e.g., phone failure, no connection, operation not allowed/supported, SIM PIN required). This standardized error reporting simplifies troubleshooting.
Documentation and Support: Quectel provides comprehensive documentation, including this AT Commands Manual, to guide users through the module's functionalities. Access to technical support via email and local offices ensures that users can get assistance with any issues or questions they encounter during deployment or operation. The revision history of the document indicates ongoing updates and improvements, reflecting a commitment to supporting the product.
Remote Management Potential: While not explicitly stated as a direct feature of the AT commands, the detailed network information and control provided by QuecCell commands lay the groundwork for sophisticated remote management systems. By integrating these AT commands into a larger application, developers can build solutions that remotely monitor network conditions, reconfigure network preferences, or diagnose connectivity issues without physical access to the device. This capability significantly reduces maintenance costs and improves operational efficiency for deployed devices.
General| Technology | GSM / GPRS |
|---|---|
| GPRS Class | Class 12 |
| Operating Temperature | -40°C to +85°C |
| Series | GSM/GPRS Module Series |
| Frequency Bands | 850/900/1800/1900MHz |
| Power Supply | Single power supply |
| Interfaces | UART |
| Protocols | TCP/IP, HTTP, FTP, PPP |
| Certifications | CE, FCC, PTCRB, GCF |
| Dimensions | Varies by model (e.g., 24mm x 24mm x 3mm) |
To Next Page
