We use US Robotics, with switch 3,5 and 8 down from desktops. If you have to change yours, make sure you power down and back up after changing the switches.
You will have to set up your Hyperterminal settings too. If you look on the face plate of your Opt 11 you should see switches, this is your baud speed for TTY 0 start with your emulation the same as that (ie 9600) if that is what the modem is plugged in to, if not, go to LD 22 and enter
PRT
ADAN TTY
This will list all the TTY's programmed, determine which you are using and set up accordingly, ie 9600 8N1.