I want to start developing project on short code sms services using C#. But I do not know where to begin. Can anyone tell me from where to start?

If you want to Transmit SMS from your mobile phone connecting your PC

mscomm32.ocx was the one I used during VB6 times, that OCX has all the command and facility to send/receive SMS using your mobile phone

In Old days I was having difficulty to connect with different kinds of mobile but I was able to get rid easily, I don't think its problem any more but tested the application since ages but once you will start working on it you will defeat the obstacles

For link :
http://www.bigresource.com/VB-How-can-I-send-AT-Commands-to-gsm-modem-using-MSComm32-ocx-or-NETComm-ocx-LanotHe0Qk.html#ElXXSgvU0f

will help for use of (AT) Commands , the method is quite simple and will not need to pay to subscribeription or per SMS fee and give full control to connect with Excel Or DB as you are using self created object, otherwise there are many 3rd Party Senders who give access to their website for sending SMS providing API's and customization like www.twilio.com and as other solution suggested


Note: MSComm32 is most reliable Component, so in case of any problem you have to check your own code.