Problem with communication between micro and the device

dehqan · Joined: 20 Nov 2011 Posts: 1

In The Name Of Allah The compassionate merciful

We want have communication between AVR/ARM Micro controller and Corus PTZ Gas volume converter ,
This device has rs232 port for local communication with a laptop through an intrinsic safe isolation
The RS232 port provides the following signals:
• transmitted data (TxD)
• received data (RxD)
• data terminal ready (DTR)
more info at page 15 of it's catalog CORUS_GUIDE_V13_ANG_FAUVE8.pdf - 4shared.com - udost

you can see Hardware architecture picture at page 6 ,

But we don't know what type data should be sent to this device from our Micro Controller and what kind data we can receive on RS232 port ?
and what does ISB do in this image ?what is it for ?
http://dehqann.byethost15.com/4.bmp

we will be so thankful if you guide us at this .

Regards dehqan