We have no way to know what address you would use. You have to use the address for your mainframe, and we don’t know what your mainframe’s address is. More commonly, a mainframe would belong to your employer, and your employer would have to tell you what address to use.
 
Tom

sir,    i am heard that we can access mainframe from our pc like mocha for as400.So my query is It is really possible?If Yes then how ?

As already stated, if your Mainframe supports 3270 emulation using TELNET, then get the IP address from your network/system administrator and the port (default 23, but could be something else) and configure Mocha TN3270 with those parameters. Depending on your setup, you might have to get someone to change your firewall to allow you access

i don’t know, it support or not  …

i am heard that ” we can access mainframe by emulator TN 3270 “. After downloading it gives me an error or it is not connected properly. Can anybody help me ? 

i am heard that ” we can access mainframe by emulator TN 3270 “.
 
There are two requirements:
 

You need Mocha 3270
You need a mainframe
 
You say that you have a copy of Mocha 3270, so you have met the first requirement. Now all you need is a mainframe. Do you have one?
 
If you don’t have a mainframe, you will have to get access to one before we can help you. When you find a mainframe that you can use, come back here to continue the question. Until then, nobody here can help you. We can’t give you a mainframe to use.
 
Tom