Accessing telnet in a unix shell account is quite simple. At the unix prompt
(often $ or your username$) type telnet, the prompt should then change
to telnet>
At this prompt you want to type op (For open)
and then the address valhalla.com 4242 (see note*)
The following would be the complete line you need type
at the telnet> prompt (all but the '*' do not type that)
op valhalla.com 4242*
Another way to use telnet from the Unix prompt is to simply type the command
telnet with the address following.
telnet valhalla.com 4242*