I need several ports to connect with rs232 lines, can I use GPIO for transmitting data?
Is the GPIO - single cable, which can transmit binary data, what is the max voltage of input and output levels ?
So, I have many questions, and maybe i need in good docs 
) it maybe examples or samples.
Thanks a lot for any help
Yes, your questions are answered in the Product Technical Specification document (or “PTS”, for short) for the specific module in question.
The “PTS” is Wavecom’s name for what would generally be known as the “Datasheet” for a microprocessor or microcontroller.
So, just as you’d have to read the “Datasheet” to answer these questions for a microprocessor or microcontroller, so you have to read the “PTS” to answer them for a Wavecom device