Keyboard Converting Guide
This is a preview of upcoming Admiral Shark's Keyboards content. This page is considered work-in-progress and should be treated as such.
The Keyboard Converting Guide is designed to help produce a tailored keyboard adapting or converting guide based on your answers to a series of questions asked to identify the keyboard and its connectivity. Please answer each question below with the answers that best apply to your keyboard.
Contents
- Connector: 5-pin 180° DIN (aka, DIN-180 or DIN-5-180)
- Looks like: MIDI connector
- Protocol: IBM PC Mode 1
- Scancodes: IBM scancode set 1
The combination of a 5-pin 180° DIN plug, IBM PC Mode 1 protocol and IBM scancode set 1 was used as the original IBM Personal Computer keyboard interface. It is nicknamed the XT keyboard interface after the IBM Personal Computer XT, used to contrast it with the later AT keyboard interface that makes use of the same physical plug and pinout but are not data-compatible with each other.
There are effectively two variants of the XT keyboard interface, one that makes use of a reset pin and one that does not. The IBM Personal Computer Keyboard (Model F, essentially the reference keyboard for this interface) likewise existed in two varieties to match, but the original type with the reset pin present is less common than the revised type. Third-party XT-compatible keyboards may be made to either standard.
Applicable keyboards
The following IBM and family keyboards are known to use this keyboard interface:
XT to USB always require active conversion. The XT keyboard interface was already a decade obsolete during the computing industry's transition from PS/2 to USB being the standard keyboard interface, so no known XT-compatible keyboards were made with internal USB support to allow a passive USB adapter to work. This also means active XT to USB converters were not common like AT and PS/2 ones, and options were limited until the 2010s with the advent of Soarer's Converter.
The aforementioned Soarer's Converter or Vial-QMK ibmpc_usb are presently the most common firmware used for converting an XT-compatible keyboard to USB. Both will advertise XT and AT support concurrently - that is normal. The following are currently available pre-made converters that are flashed with either firmware:
Note
If you already own an active PS/2 to USB converter running Soarer's Converter ot Vial-QMK ibmpc_usb firmware, you can reuse the converter for an XT keyboard if you combine it with a passive AT to PS/2 adapter.
Converting to AT or PS/2
XT to AT generally requires active conversion. XT and AT keyboard interfaces may use the same plug, but they are not normally compatible with each other. Some third-party XT-compatible keyboards had a switch to change between XT and AT compatibility, but this was not the case for IBM and family keyboards. If you have a third-party keyboard, please check for such a switch. If it was present, it could be labelled "XT/AT", "X/A" or "8088/80286". If present and you switch the keyboard to AT mode, you can then subsequently follow passive AT to PS/2 adaption instructions with ease as well.
Otherwise, active converter solutions for XT to AT indeed exist, but options are limited and prices for such may reflect that. Hagstrom's KE18-XTAT-PS/2 is perhaps the most well-known XT to PS/2 converter. The output of this converter can be further passively adapted from PS/2 to AT if needed.