LTE modem can be access with prepared daemon included in OS images or directly by communicating with the modem.
The unipi-lte package, which makes the use of an LTE modem available, also includes a virtual serial line for communication with the modem via AT commands (Cat 1 - EC200U-EUAB/EC200U-EUAP, Cat 4 - EC200A-EUHA). Modem settings could be managed for example, by the minicom program, directly from the unit's Linux console (by SSH access). GNSS configuration and communication uses specific AT commands (EC200U-EUAP only).
In the control SW (Node-RED, etc.) the serial line can be used, for example, to send and receive SMS messages or calls.
The table below provide information on how LTE modem is available and how it is mapped into Linux.
| Modem's serial line for AT commands | /run/unipi-plc/by-sys/lte.1/tty_at1 |
| Modem's GNSS serial line (EC200U-EUAP only) | /run/unipi-plc/by-sys/lte.1/tty_gnss |
Since this is a virtual serial line, communication parameters (baudrate, parity, etc.) can be selected arbitrarily.
Attention:
When using the virtual serial lines listed above in user program, it is necessary to release it while the modem is restarting, otherwise serial line links might be created incorrectly.
