Python SMS Interface for Zyxel LTE3302 Series Router

This is a simple program to send SMS messages via a 4G LTE Router. The router I am using is a Zyxel LTE3302 Series router which provides a 4G hotspot for my robots. The data package I am using allows for unlimited texts, so this seems like an attractive option for cool communication between me and my robot.

Unfortunately the router does not offer an API to enable a user to send texts - the only supported interface is via a the router's adminstration web pages. The program apes the browser HTML GET calls to send a text.

Setup and usage

1. Clone this repository

git clone https://github.com/hopkira/4G-LTE-SMS.git

2. In the resulting directory create a secrets.py file

cd 4G-LTE-SMS
nano secrets.py

3. Add the following content

userid="admin" # the user id to access your router
password="1234" # the password to access your router
number="01234567890" # a default number to send messages to
ip="192.168.1.1" # the IP address of your router

4. You can now use this program from the command line:

python3 fourgsms.py -m 'This is my message' -n 'phone_no_to_text'

5. Alternatively you can import it as a python module and use it in your own programs. The logon transaction takes quite a while at the moment, but you can send multiple messages once logged on, though I would recommend leaving at least a second between messages.

import fourgsms as sms
import time
mySMS = sms.SMS(sms.secrets.ip)
mySMS.logon(sms.secrets.userid, sms.secrets.password)
mySMS.send(sms.secrets.number, "First message")
time.sleep(5.0)
mySMS.send(sms.secrets.number, "Second message")
time.sleep(5.0)
mySMS.send(sms.secrets.number, "Third message")

How does this work?

The program was created by analysing the traffic between my Mac and the Router during logon and SMS text sending activities. It was clear that to send a text, four interactions had to be sent from the browser using HTTP GET.

1. The logon time is retrieved from the router
2. A logon interaction that then creates a session cookie called AMSESSIONID
3. A SMS interaction that pre-populates the SMS message details (and uses the same cookie above)
4. A final 'send' instruction that sends the text (and uses the same session cookie again)

Other routers

D‑Link's DWR‑921 4G LTE Router appears to have a near identical inteface, so it is possible the code will work for it too, or just with some minor changes (but I can't test this). Given the Zyxel and D-Link software are impossibly similar, it is quite possible that the routers are using identical software that has been separately branded. If this code works with your 4G Router and it isn't listed here, please let me know via an Issue or Comment and I will update this README.