Java AT Command Tester for GMS modems



AT command tester is a free online software tool that is used to test AT commands and other functionalities of GSM modems. The friendly user interface allows developers to,

  • Configure and connect to modem ports
  • Send single or batch of AT commands
  • Perform modem diagnostics
  • Establish 3G or GPRS call
  • Collect and save modem logs

Port Configuration

AT Command Tester uses Java-based serial drivers to interface to the modem. The ‘Find Ports’ button will automatically find all ports available in the system. The user can connect the appropriate modem port with the desired port speed.

Command mode

After connecting successfully to the modem, users can send single AT commands under ‘Command Mode’ tab. The drop down provides list provide list of AT commands with description and examples. The users can modify or enter their own AT command in the text box.Script Mode

Users can send batch of AT commands under the ‘Script Mode’ tab. They can also save and load the script from the local machine. Users can develop their own scripts for specific set of tasks such as call setup , send SMS, HTTP access etc. Users can also include descriptive comments in their script.




Users can perform basic troubleshooting of the modem under the ‘Diagnostics’ tab. Here the AT Command Tester tool sends the required AT commands and provides descriptive output about the state of the modem.


Data Call

The ‘Data Call’ tab provides the interfaces to setup data call with the GSM network. ‘Get PDP Contexts’ button will list all the PDP context profiles stored on the SIM. Users can also add or update new PDP context profile. Users can then connect to the selected profile. AT Command Tester will first check whether the device is registered on the network. If so, it will attach and connect to the network with the selected PDP context credentials.


AT Command Tester can also be used voice calls, both incoming and outgoing.


The phone book stored on the SIM can be edited/added/deleted through the ‘Phone  Book tab of the AT Command Tester.


Network selection feature allows the user to select the available network.


The HTTP function is only implemented for the SIMCOM modules. Users can test HTTP Get and Post using the AT Command Tester.


The FTP function is currently implemented only for SIMCOM modules. This allows users to test FTP Get and Put functions using the SIMCOM modules.

More feature additions such as voice call, SMS, Phone book functions, HTTP, FTP, TCP/IP are planned for AT Command Tester tool. Suggestions from this blog readers are also welcome.

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