How to get data from Panasonic Pabx KX-TDA200 via RS232 using c#

Question

HI verybody!

Does anybody have more experiences to connect PC to PABX?
Please show me how to get data from Panasonic pabx KX-TDA200 via RS232 using C# or VB6.
and put input data to textbox for datagridview for me.
Thanks in advance!