Send SMS using AT commands over the TTY of a Cellular modem. Supports Unicode international characters and emojis.

sendsms

#!/bin/sh -e

# Usage: sendsms +375555555 "some text i want to send"

TELFNUMB="$1"
SMSTEXT="$2"
MODEM="${3:-/dev/ttyUSB2}"
TIMEOUT="${4:-1}"

# Text encoding
to_ucs2() {
  python3 -c "import sys; print(sys.argv[1].encode('utf_16_be').hex())" "$1"
}

# Chat with modem
exec < $MODEM > $MODEM

# Configure modem
chat TIMEOUT $TIMEOUT "" "AT" "OK"
chat TIMEOUT $TIMEOUT "" "AT+CMGF=1" "OK"
chat TIMEOUT $TIMEOUT "" "AT+CSCS=\"UCS2\"" "OK"
chat TIMEOUT $TIMEOUT "" "AT+CSMP=17,167,0,25" "OK"

# Send message
chat TIMEOUT $TIMEOUT "" "AT+CMGS=\"$(to_ucs2 ${TELFNUMB})\"" ">"
chat TIMEOUT $TIMEOUT "" "$(to_ucs2 "${SMSTEXT}")^Z" "OK"

Change encoding to support international characters and emojis.

References:

• https://stackoverflow.com/questions/24950901/send-unicode-usc2-sms-with-at-commands
• https://m2msupport.net/m2msupport/sms-send-sms-in-other-languages/
• http://www.testech-elect.com/enfora/tutorial_send_receive_sms_using_gsm_modem.htm

Originally adapted from https://gist.github.com/artizirk/6307533