I'd like to write a shell script that will enter '1', for example. How
do you do that?
You know, so instead of writing

echo "Enter 1 or 2"
read onetwo

and waiting for the user to enter a 1 or 2,
I'd like the script to act like someone entered a 1, or 2. Is there a
hex value for the return key or something?

you want expect or the perl telnet module

check this out for expect http://www.oreilly.com/catalog/expect/chapter/ch03.html

both of these allow you to automate many tasks that usually require user input, both have "Enter" capabilities