As many of you know, GSM is the only technology that supports the SENDING of SMS from the handset. You can use this feature to send SMS to another handset, or to a gateway. But how do you find out if the person you sent the message to has picked it up? On the menu of most GSM phones you'll find an option for "Delivery Reports", but this doesn't seem to work on Microcell Connexions in Canada, nor on some other GSM networks in North America.
But here's something that DOES WORK. Add a string of three 1's to the beginning of your message, something like this:
111Hi Joe, are you coming to the meeting?
Your recipient won't get the "111" at the beginning of the message, but you will be sent a confirmation message immediately after your recipient's phone downloads the message from the switch. This doesn't guarantee he's read your message, but it does guarantee that it is now IN his phone. If the message "goes stale" and is deleted from the carrier's system before it is picked up, you will also receive a confirmation of this.