SNKB-M2005-BT4-122
Notes
This keyboard originally came into my possession with worn case texture and a yellowed set of Unicomp's sparkly blue-grey keycaps with IBM 5250 US English legends. The keyboard has been partially restored with a brand-new Unicomp PC-122 case (original lock-light overlay also transferred to the new case) and a combination of Unicomp's pearl/pebble US and 3270 PC keycap sets, and several UK ISO and custom (Fn and 1u backspace) keycaps. I plan to purchase and install a more authentic grey 5250 keycap set at the earliest convenience. This keyboard was also featured in my Differences between and classifications of 122-key Model Ms comparison topic.
| Full Name | Affirmative Computer Products 5250 Emulation Keyboard |
| Part NumberPart Number The number used to describe this keyboard's specific release; usually specific for a target region, language or SKU, etc. |
AC40956 |
| Market Model Name/Feature CodeMarket Model Name/Feature Code The consumer-friendly model number describing this keyboard as a part of a range of products, usually irrespective of target region, language or SKU. |
1225T |
| TypeType A designation from my own type naming scheme used to categorise this keyboard with or from others by their common features and market intent but may/may not be derived from official names. |
Model M Type IV 122-key Emulator Converged Keyboard |
| NicknameNickname A [keyboard enthusiast] community given name for this keyboard. It can be a shortening of its name and properties, a more abstract term, a real-life reference, or metonymy. |
Battlecruiser |
| Key-switchesKey-switches The name of the known switching mechanism that lies under this keyboard's keys. |
IBM membrane buckling springs |
| Original KeycapsOriginal Keycaps The keyboard's original keycaps' material and text/symbol printing technique. |
PBT with dye-sublimated legends |
| FeetFeet The style of this keyboard's flip-out or extendable feet. If applicable, this may also state how many levels of height adjustment are available and whether the feet could be rubberised. |
Single-setting elongated flip-out feet |
| ProtocolProtocol The protocol(s) this keyboard can use to speak to the host computer (eg, scancode sets). |
IBM scancode set 2 |
| ConnectionConnection The keyboard-to-host connection. This is could be a description of a cable (its colour, whether its coiled, whether its detachable, and what connector is at its end) or the name of a wireless technology. |
Black coiled-style fixed PS/2 mini-DIN cable |
| Form FactorForm Factor The standardised or universally acknowledged name for this keyboard's layout form factor. |
120% |
| Production Date | 2005-03-28 |
| Acquisition Date | 2020-10-05 |
About this keyboard type
The Type IV 122-key Model M Function Key Keyboard is a version of the Type III designed to be natively compatible with PCs to serve in terminal emulation roles. Officially called the IBM Personal System/2 Host Connected Keyboard, Type IVs were relatively rare but for a long time were the only 122-key Model Ms easily capable of modern usage until Soarer's Converter became widespread. Visually, Type IVs look like Type IIIs except all IBM-branded versions had lock-light LEDs as standard and come with modular SDL connections capable of accepting an AT or PS/2 plug cable. IBM also started a practice producing Type IVs under third-party branding to companies that offer terminal emulation services, which Unicomp continues to do to this day. Unicomp also produces a version of the Type IV for consumer usage called the Unicomp PC-122. Like the Type IIIs, the 24-key function key block was only labelled with an "Fxx" nomenclature.
