SMS with GSM Modem

Last time I wrote about sending SMS using online tools. The main problem there remains 2 way communication. Luckily, there's a simple solution to receiving problem. Since the start of 3Gmobile internet, GSM modems became quite ubiqitous and reasonably cheap. Just like the SMS software. I used Smstools that proved to be a snap to install and use.

wget http://smstools3.kekekasvi.com/packages/smstools3-3.1.3.tar.gz
tar -xzf smstools3-3.1.3.tar.gz
cd smstools3
sudo ./install.sh

I am using Huawei Mobile Modem E270 and E170 from Starhub. The only change I had to make now is update the config file. Here's my config file /etc/smstools.conf

devices = GSM1
logfile = /var/log/smsd.log
loglevel = 7

[GSM1]
device = /dev/tty.HUAWEIMobile-Modem
incoming = yes
#pin = 1111
init = AT+CNMI=2,0,0,2,1

After that just start/restart the smsd daemon

sudo killall smsd; sudo smsd;

Sending of SMS is now as simple as

sudo sendsms +6584199983 'Your SMS message....'

or just put SMS File to /var/spool/sms/outgoing/

To: 491721234567

Hello, this is the sms.

More info about the structure of the file is here.

As for receiving, all the received messages will be downloaded to /var/spool/sms/incoming/ so all you have to do is create a cronjob to check this folder for new messages and then forward the message to your application.