IBM Model F Buckling Spring Keyboard

IBM (or more specifically, Richard Hunter Harris at IBM) developed the Model F capacitive buckling spring switch for production in 1981. Its most prominent use was in the IBM PC 5150 keyboards at the time. Lauded as having better 'feel' than the Model M keyboards, they eradicate the need for a rubber membrane underneath the switches, and instead just have the switch 'foot' touching against two contact pads.

The Model F switches are extremely light to the touch, and not as heavy as Model M switches. As such, not everyone immediately prefers them if they are more accustomed to heavier switches. They also generally have excessive spring sound and clatter-- more so than early Model Ms. The sound is a huge problem for those who like superior keyboards without the sound; whereas others prefer the sound will most likely prefer these keyboards.

Downloads

• 122 Model F to Teensy Pinout
• Soarer's Converter 1.12 Documentation
• Soarer's Converter 1.12 Files
• Teensy Flashing Application

Model F Variants

Here's a list of all major Model Fs:

• XT Model F (PN: ?)
• AT Model F (PN: ?)
• 122 Terminal Model F (PN: 611034x)
• 3290 Model F (PN: 1387033)
• 4980 Model F (PN: ?)
• Displaywriter Model F (PN: ?)

Additional Notes:

• The 3290 Model F keyboards are considered as a "space saving" 122 Terminal in that they lack the numpad.
• The Terminal 122 Model F keyboards can be modded with a USB controller to be used on any modern computer.

Differences Between Models

Generally all Model Fs seem to be consistent that I've tried. The original PC 5150 Model F is probably the 'crispest' due to the fact it is the most compact version. The Model F spacebar is notorious for being rather odd; Model M users will find it a bit alienating if they're not used to it. I'm personally not a fan of any of the early Model F layouts and always modify them to be more like the Model M.