def disconnect_3g(): subprocess.run(["poff", "huawei-e173"]) Add a health check (ping or check interface status):
# /etc/usb_modeswitch.d/12d1:1c0b TargetVendor=0x12d1 TargetProduct=0x14fe MessageContent="55534243123456780000000000000011062000000100000000000000000000" Or programmatically with libusb :
def get_signal_quality(port="/dev/ttyUSB0"): ser = serial.Serial(port, 115200, timeout=2) ser.write(b"AT+CSQ\r\n") resp = ser.read(100) ser.close() # Parse +CSQ: <rssi>,<ber> if "+CSQ:" in resp.decode(): parts = resp.decode().split("+CSQ:")[1].strip().split(",") rssi = int(parts[0]) # 0-31, 99=unknown return rssi * 2 - 113 # dBm approx return None firmware modem 3g huawei e173 maroc telecom
screen /dev/ttyUSB0 115200 AT+COPS? # Should return "MT" (Maroc Telecom) AT+CSQ # Signal strength AT+CGDCONT=1,"IP","mtnet" ATD*99# # Should show CONNECT Then start pppd manually to test connection. If this is for a product feature , you’d deliver:
/dev/ttyUSB2 115200 connect '/usr/sbin/chat -v -f /etc/chatscripts/3g-chat' user "mtnet" password "mtnet" noauth defaultroute replacedefaultroute usepeerdns persist maxfail 0 ( /etc/chatscripts/3g-chat ): def disconnect_3g(): subprocess
ABORT "BUSY" ABORT "NO CARRIER" ABORT "ERROR" TIMEOUT 10 "" "ATZ" OK "ATE0" OK "AT+CGDCONT=1,\"IP\",\"mtnet\"" OK "ATD*99#" CONNECT "" You can implement a CLI/daemon with these functions: Python example using pyserial + pppd import serial import subprocess import time def switch_modem_mode(): # Run usb_modeswitch subprocess.run(["usb_modeswitch", "-v", "0x12d1", "-p", "0x1c0b", "-M", "55534243123456780000000000000011062000000100000000000000000000"])
def connect_3g(): subprocess.run(["pon", "huawei-e173"]) def disconnect_3g(): subprocess.run(["poff"
(example config):