Editing IBM Model F (section)

===IBM 104-key Model F Keyboards===
The 104-key Model F was the predecessor to the 122-key Model F keyboards, and is colloquially referred to as the "Unsaver". It is a common misconception that the Unsaver was introduced after the 122-key Model F keyboards, when in fact it was introduced several months ahead of the first terminal [emulator] with a 122-key Model F keyboard. The Unsaver was primarily associated with two IBM systems - the IBM 3290 Information Panel series and the IBM 5080 Graphics System. The 3290 Model 1 (3290-1) was announced in March 1983<ref name="ibm183-033" /> (by contrast, the IBM 3270 Personal Computer that introduced the 122-key Model F was announced in October 1983<ref name="ibm183-129" />). The 5080 was announced in November 1983<ref name="ibm183-145" />. Finally, the IBM 3290 Model 2 series was announced in October 1985 with a model 220 (that included an Unsaver) and 230 (that included a 122-key Model M)<ref name="ibm185-115" />.

There were two major design iterations, or types, of Unsaver. The first type, which was intended for 3290-1 and 5080, featured one 15-pin (DA-15) and one 25-pin (DB-25) D-subminiature connector on the back. The DB-25 connector was used to connect the keyboard to a 3290-1 or 5080's 5085 attachment processor, and the DA-15 connector was used to connect peripherals such as the 5080's Lighted Program Function Keyboard or the 3290-1's and 5080's 24/25 key keypad. On the bottom of Type I, there was an adjustable clicker and a [redundant] bank of 4 DIP switches. The second type of the Unsaver, which was introduced with 3290-220, removed Type I's clicker and changed the location and size (to 8-position) of its DIP switch bank. Type II retains the holes on the back of the case for Type I's D-subminiature connectors, but they are hidden behind a plastic cover with a notch for a fixed cable terminating in a 240° 5-pin DIN connector.

IBM later offered a visually similar 104-key keyboard for the IBM 3191 Display Station<ref name="ibm187-025" />, IBM 3192 Color Display Station<ref name="worthpoint1868331207" /> and 3270-compatible IBM InfoWindow Display Stations (ie, 3471<ref name="ibm3471" />and 3472). These were referred to as "Quiet Touch" keyboards and were made by Micro Switch and used their [[Micro Switch ST Series|ST Series]] switches. As such, these are not related to Model F keyboards on a technical level - they were constructed differently to the 104-key Model F keyboards and the assemblies cannot be switched between the keyboards. A Model M assembly also cannot be modified to fit in the Quiet Touch 104-key keyboard.

<gallery widths=250 heights=127 caption="IBM 104-key keyboards">
File:1387033.jpg|3290-2 terminal keyboard, part number 1387033. 
File:73X3860.jpg|Micro Switch ST 104-key terminal keyboard, part number 73X3860.
</gallery>