IBM 3270 Hardware User's Manual page 53

2. If the long legs are too high, push the long
legs back into the bottom of the keyboard.
We recommend the short legs.
3. If the short legs are also too high, push them
back also.
What to Do Next
You should now have all your units set up,
connected to each other, plugged in, and
arranged comfortably on your desk. You are
ready to test your system. Go on to "Step 4,
Checking Out the 3270 PC with the Power-On
Self Test."
2-36 Book 1 - 3270 PC Work Station User's Guide