I've had a Newton Keyboard to go along with my MessagePad 2100 for years, and they have always played well together.
Today, though, I find that neither shift key on the keyboard is doing anything.
Typing input with a shift key depressed yields a lower-case letter (or the 'lower-case' typographical symbol on a key-- ';' instead of ':').
Caps Lock still provides capital letters.
Every other key works, including Ctrl, Option and open-Apple.
Same behavior when used with an eMate 300.
Any ideas as to what might be causing this behavior? Is it likely within the keyboard, or in the serial adapter?