Send SMS from USB 3G viettel using Raspberry PI https://sonnguyen.ws/send-sms-from-raspberry-pi-with-usb-3g/

sms_usb_3g_viettel.py

import serial

def send_text(number, text, path='/dev/ttyUSB1'):
    ser = serial.Serial(path, timeout=1)
    ser.write('AT+CMGF=%d\r' % 1)
    ser.write('AT+CMGS="%s"\r' % number)
    ser.write('%s\x1a' % text)
    print ser.readlines()
    ser.close()

send_text('098xxxxxx', 'hey how are you?')