debugging with ddd ...(how to input data...)

[LDP73]

hello !
How are you?

I'm analizing a telnet client program by using ddd.
In the program, I finished to analyze to the part where a telnet
server and a client negotiate options.
But, I don't know how to input data when debugger is waiting data
from stdin through select function. So, I can't continue to analyze
from the part where I should give the debugger a login name and password.
I've looked for a manual to find out how to do it, but I couldn't.

I would be appreciate it if you tell me the way how to do it.
Did you understand what I want? Sorry for my bad English.
Have a nice day!