sendsms.py

# reg-exp
import re
# use pyserial
import serial
from time import sleep

def checkOK():
    isOK = False
    lines = ser.readlines()
    for line in lines:
        print line
        if re.match(r'^OK', line):
            isOK = True

    if isOK:
        print '---- OK!'
    else:
        print '---- FAIL!'

# replace /dev/ttyUSB3 to your device path
ser = serial.Serial('/dev/ttyUSB3', 115200, timeout=1)
# clear serial command
ser.write('ATZ\r')
# Set operating mode see: http://www.developershome.com/sms/operatingMode2.asp
ser.write('AT+CMGF=1\r')

# Read buffer
ser.readlines()

# To send SMS, first set destination number
# see: http://www.developershome.com/sms/sendSmsByAtCommands.asp
ser.write('AT+CMGS="0841112222"\r')
# Then write the message
ser.write('Hello! From SIM Card\r')
# .. can have many lines
ser.write('-- Second line\r')
# .. write char 26 (Ctrl-z) to end message body
ser.write(chr(26))

sleep(1) # wait for response
checkOK()

ser.close()