# Development

- [SSH Terminal](/dev/ssh.md): The command-line interface (CLI) means interacting with the router system where the user issues commands to the router system through command lines.
- [VI Editor](/dev/ssh/vi.md): VI Editor is a powerful and efficient text editor once you become familiar with its commands.
- [Crontab Syntax](/dev/ssh/cron.md)
- [Command Sets](/dev/command.md)
- [MMCLI Commands](/dev/command/mmcli.md)
- [SMS Message](/dev/command/mmcli/sms-message.md): The mobile modem supports SMS service for sending messages online.
- [Location 3GPP GPS](/dev/command/mmcli/3gpp-gps.md)
- [AT Commands](/dev/command/at-5g.md): The mobile modem can be configured by AT commands. Different mobile modems use the different AT commands. Below are the AT commands for 5G modems using on the 5G SIM routers.
- [AT+QAGPIO](/dev/command/at-5g/at-qagpio.md): AT+QAGPIO is an AT command used in Quectel cellular modules to set the output level of a GPIO pin on the AP or PMU. It can control external devices or sensors connected to the pin.
- [AT+QTEMP](/dev/command/at-5g/at-qtemp.md): The AT+QTEMP command retrieves the temperature value of the MT (Module Temperature). This command is supported by Quectel cellular modules and allows you to monitor the module's temperature.
- [AT+COPS](/dev/command/at-5g/at-cops.md): The AT+COPS command allows retrieving information about the current mobile network operators and their status. It facilitates selecting automatic or manual network selection mode.
- [AT+QENG](/dev/command/at-5g/qeng.md)
- [AT+QCAINFO](/dev/command/at-5g/qcainfo.md)
- [Bootloader](/dev/bootloader.md): The Bootloader initializes the hardware and loads the operating system for starting up the router and preparing it to run the firmware system.
- [Custom-Build Firmware](/dev/custom.md)