Hi,
This really depends on your instrument. If your instrument works on the EOS strategy then you will need to configure it to do so. But for sending a command you will want to put the character in the string. For example if a carridge return is the EOS char, type ibwrt "*IDN\n".
I would recommend using the ibdev command also. This will ask you a series of questions that will set up your board and communication. You can find more information on this at http://www.ni.com/support/gpib/max/ibic.htm.
Some other questions are:
1) Does *IDN? or any other command work?
2) Have you tried to communicate with other instruments?
3) What hardware do you have?
Hope this helps out!
Best Regards,
Aaron K.
Application Engineer
National Inst
ruments