C# Windows Service for sending text messages (SMS) from a cell phone
Sat, 24th January 2009 - 02:05 PM   |   4203 views   |  comments

Last year we (the TeaBreak team) thought of holding a Hi-Tea event for bloggers in Pakistan. We agreed that it would a nice idea to ask bloggers RSVP online so that we can keep things in order. The event went good but the good part was also an SMS-based RSVP system!

A couple of hours of coding and I came up with a small script that would take a person's name, email and mobile number. The script will later send an SMS containing a unique ticket number. The ticket number served as an entry pass as we had limited seats for the event. Those who signed up for RSVP got a tid bit surprised with SMS mechanism, although I thought it to be quite primitive.

Here's the C# Windows Service that was running on my computer back then that was sending all the SMSes to folks. The service would connect to a MySQL database on my hosted server and fetch any pending messages (SMSes) that were to be sent. I hooked up my old Samsung phone with a serial data cable to my computer.

I thought to share it here just in case if anybody is looking for enjoying some kind of SMS feature in their applications.

Click here to download the C# code

(I am only uploading the class file rather then the complete VS project - SMSController.cs - you can build it in a windows service or whatever you prefer)

Pointers on how SMS sending and receiving works:

1. You connect a GSM modem or a mobile phone to your computer which appears as a communication port (COM1, COM2, etc.)
2. You send extended "AT" commands to the COM port to communicate
3. Here's a tutorial on the "AT" commands for GSM modems/phones:
   http://www.developershome.com/sms/atCommandsIntro.asp
   

This is just a very basic class, if you need help on multimedia messages (MMS) support, or come across some issues etc. you can get in touch with me.