Of course sending an SMS via an attached phone or GSM modem using AT commands in PDU mode is fun . Sometimes you just want to send a plain text message from your application and you don’t want to bother with phones, SIM cards, data plans, PDU mode and so on.
In these cases the easiest solution would be to use an SMTP to SMS gateway. SMTP is the protocol used to send email (Simple Mail Transfer Protocol). What such a gateway does:
- is receive an email
- look at the intended recipient
- figure out a phone-number from/for that recipient
- send the text of the email as an SMS to the recipient’s phone
You could send an SMS message this way using any SMTP library (they come with .NET, JDK and many open source libraries are available to do this from C or C++).
There is a really simple way to test this: just send an email from your email client.
Of course there are some limitations: