i read this i even used communication example of RS command in this project
Care to share?
Are you saying that the example only showed sending a '3'? Hard to believe but possible.
As for the handshaking, I haven't dealt with that for 20-odd years and I can't remember what does what these days. You could probably get away with tying a couple of lines to active levels or together, the signals in question are CD, DTR and DSR.
But without the access to the proper protocol spec I see little point in carrying on.