I need to know what kind of characters I can't put in my message, how to format it and if I can put spaces at the end of message. If some knows some about it, some bug, some hit, please tell me.
You can safely send ASCII information over SMS, provided you are encoding your characters to Binary PDU first.
Some of the newer GSM modems like Wavecom and Multitech would even allow direct ASCII or even Unicode data to be sent.
To check whether your modem supports SMS Text mode (instead of Binary PDU mode) use the following command
If the response is "OK" this is supported. That means you can send ASCII character set messages (No Unicode though)