📞 GSM Call Forwarding Scheduler

Automatic management of call forwarding on a GSM modem based on a schedule stored in an Excel file.

Overview

The script periodically reads the schedule.xlsx file and checks whether the current time falls within any defined time range.
If it does — it enables call forwarding to the specified number.
If not — it disables call forwarding.

Communication with the GSM modem is done via serial port using AT commands.

Hardware Compatibility

This project is developed and tested on:

• Raspberry Pi 5 (8 GB RAM)
• SIM7600E-H 4G DONGLE

The script works reliably on this hardware configuration.
Other GSM/LTE modems that support AT+CCFC and standard call-control AT commands should also work, but they have not been tested.

schedule.xlsx structure

The file must contain headers in row 1 and data starting from row 2:

Start Date	End Date	Start Time	End Time	Number
2025-01-10	2025-01-10	08:00	16:00	123456789

Each row defines one active forwarding time window.

Requirements

• Python 3.7+
• Required libraries:

  pip install pyserial openpyxl pytz

• A GSM modem supporting:
  • AT+CCFC (call forwarding)
  • AT+CLIP
• Access to /dev/ttyUSB2 or another configured serial port

Configuration

Editable parameters are located at the top of the script:

PORT = "/dev/ttyUSB2"
BAUD = 115200
XLSX_FILE = "schedule.xlsx"
LOCAL_TZ = pytz.timezone("Europe/Warsaw")

Running the script

python3 forwarder.py

The script will:

• connect to the GSM modem,
• check the schedule every 60 seconds,
• automatically enable or disable call forwarding,
• print all AT commands and modem responses.

Loop logic

Every minute the script performs:

1. Load the schedule from Excel.
2. Determine if the current time falls into any defined time range.
3. If yes — enable call forwarding:

   AT+CCFC=0,3,"NUMBER",145
   

4. If no — disable call forwarding:

   AT+CCFC=0,0
   

The script remembers the last active number to avoid sending redundant commands.

Stopping the script

On Ctrl+C:

• call forwarding is automatically disabled,
• the serial port is closed safely.

Notes

• The Excel file must not be open in edit mode — the script needs to read it.
• All dates and times are interpreted in the Europe/Warsaw timezone.
• Invalid rows in the schedule are skipped with a warning.

License

This project is licensed under the MIT permissive license.