What adapter or converter do I need for my keyboard?

Now that you've got your vintage keyboard, you may be wondering "how can I get it operational on your computer?" This part of the ASK Buyer's Guide will cover many common types of keyboard connections and describe to you possible solutions to get various vintage keyboards operating with your modern PC. Whilst this guide is still primarily intended for IBM and family keyboards, a lot of information on XT, AT and PS/2 keyboards are transferable to non-IBM keyboards as well.

Contents

Introduction & types of converters

This section of the ASK Buyer's Guide is designed to make it as easy as possible to access the information you need to get your Model F, Model M or even third-party keyboard up and running on your modern devices! Below will cover the basic kinds of converters that will be referenced throughout this guide. Before you begin though, if there are any terms that you're not familiar with, you can try referring to the Keyboard Dictionary for help.

Passive adapter

Passive adapters (aka, shape changers) are devices that swap from one physical interface to another without any electronics - one end is wired to the other without interruption. Such devices are useful for allowing something to connect with a physically different but compatible connector, such as an AT (full-size DIN) keyboard into a PS/2 (Mini-DIN) compatible computer or more commonly today Type-A USB to micro-B USB or Type-C USB (and vice versa). However, if either device being connected through such an adapter doesn't support the other at a protocol or software level, it will fail to work. All Model Fs and Model Ms that are not already USB will not work with passive AT or PS/2 to USB adapters since neither type of keyboard supports USB's HID protocol at the firmware level. Many third-party AT or PS/2 keyboards (especially those made before the late '90s) will also fail to work with a passive AT or PS/2 to USB adapter. However, adapting an IBM PC/AT Model F to fit a PS/2 port is an example where a passive adapter may be helpful.

Passive adapters almost always look as simple of a device as they are. They are usually very compact, and if there is any cable separating the two ends, it's probably relatively thin and uninterrupted. Additionally, passive PS/2 to USB adapters are usually fully coloured in purple (keyboard) or green (mouse).

Simple active converter

Active converters are devices that not only swap from one physical interface to another, but they also perform some sort of electronic processing to convert one protocol to another. They can do what passive adapters can't - get two normally foreign devices communicating with each other. In some cases, active converters can even allow keyboards that weren't designed to be hot-swapped to be connected and disconnected whilst the PC is running (though trying this is still generally not recommended). Most active converters such as the type shown are non-customisable - the firmware the converter has will be the one it will always have. Remapping keys (for example) will have to be done with a software utility solution like AutoHotkey or via utilities such as Registry Editor on Windows and xmodmap on Linux installations using X.Org Server.

Active converters like PS/2 to USB types typically take the form of a cable with a box in the middle housing its integrated circuitry (IC). More often than not, active PS/2 to USB converters will also provide a mouse PS/2 port although it doesn't need to be populated for the converter to work.

Advanced active converter

There is also a 'high-end' to the active converter market that can offer physical and electrical conversion for more unique types of keyboard connections and may grant quality-of-life enhancement features such as hardware-level layers, macros or remap creation. For vintage IBM and family keyboards, the majority of such converters are running Soarer's Converter firmware. However, QMK and TMK options have recently gained more traction as Soarer's Converter firmware hasn't been updated in many years.

Guide table

If you're not sure what the name of your keyboard's port or plug is, you can use the table below to find the relevant section you need to read. Note that some of the connectors might appear similar, so please look at all the photos before going to another section and especially pay close attention to how the pins inside your keyboard's port or plug are arranged. If you have a Model F or Model M keyboard with a connector that doesn't appear on this list, feel free to post on /r/ModelM asking for help or consult deskthority.

Using an XT keyboard

This style of keyboard connector was introduced with the IBM 5150 PC and its Model F keyboard in 1981. It shares the same plug with the later AT standard although they are not compatible with each other. The standard uses set 1 scancodes and is retroactively named "XT" after 1983's IBM 5160 PC/XT that was compatible with the original PC to differentiate it from the later AT standard.

Converting to USB

Unlike the later AT standard, XT has limited conversion options to USB since unlike AT thanks to PS/2, XT was a long-obsolete standard by the time USB was created. As such, a higher-cost bespoke active converter is required much like for IBM terminal keyboards. Soarer's Converter is presently the most common XT to USB compatible converter, which became and remains the go-to solution. Soarer's Converters can be bought premade from orihalcon's eBay store or you can assemble one yourself. TMK and QMK alternatives to Soarer's Converter exist but have only gained traction relatively recently. They can also be bought premade or assembled yourself.

Converting to AT or PS/2

XT cannot be passively converted to AT or PS/2 despite XT and AT standards making use of the same plug, however, active conversion solutions exist but options are limited and they're priced to 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.

Specific parts & resources

See Further reading & resources for potentially more resources

Using a DIN-style terminal keyboard

This style of connector is common for IBM 104-key and 122-key keyboards from the 1980s. Some 102 or 103-key keyboards made also use this connector. It is designed for terminal keyboards, thus it is not easily convertible with traditional store-bought converters.

Converting to USB

Since both the physical connector and scancodes are different to XT, AT and PS/2 connections, a bespoke active converter is required. And since terminal keyboards like the ones that use these were not consumer products, no converter for them can be found in traditional stores or online retailers. It's only during the previous decade that an easily accessible converter appeared - Soarer's Converter, which became and remains the go-to solution. Soarer's Converters can be bought premade from orihalcon's eBay store or you can assemble one yourself. TMK and QMK alternatives to Soarer's Converter exist but have only gained traction relatively recently. They can also be bought premade or assembled yourself.

Specific parts & resources

See Further reading & resources for potentially more resources

Using an AT keyboard

This style of connector and even its pinout are shared with the earlier XT standard and were the most common PC-compatible keyboard connector before PS/2. It is forward compatible with PS/2 through passive adapters thanks to PS/2 continuing to use the same set 2 scancodes. The first computer to implement set 2/AT was the IBM 5170 PC/AT in 1984, which is also AT's namesake.

Converting to USB

Since AT and PS/2 are compatible, essentially everything regarding converting PS/2 keyboards to USB applies to AT but with the added step of using a passive DIN-180 to PS/2 adapter. However, since AT keyboards far predate USB, passive PS/2 to USB adapters will not work at all. But through the former mentioned passive adapter, well-known active PS/2 to USB converters such as the Perixx PERIPRO-401 and Monoprice's USB to PS/2 dual PS/2 can be used. If advanced customisation features such as hardware-side (ie, free from constantly running software) layer, macro or remap creation are desired, Soarer's Converter is a well-known 'up market' option and is available in DIN-180 form. Soarer's Converters can be bought premade from orihalcon's eBay store or you can assemble one yourself. TMK and QMK alternatives to Soarer's Converter exist but have only gained traction relatively recently. They can also be bought premade or assembled yourself.

Converting to XT

The XT and AT keyboard standards are not compatible despite both standards making use of the same plug, thus if connecting an AT keyboard to an XT-class PC such as an IBM 5150 PC or IBM 5160 PC/XT is desired, an active converter is required. Monotech PCs' PS/2 to XT Keyboard Converter and Hagstrom's KE18-ATXT-PS/2 are two known PS/2 (which is AT compatible) to XT keyboard converters. Both can be used alongside a passive AT to PS/2 adapter.

Converting to PS/2

Again since AT and PS/2 are fully compatible with each other, a simple passive DIN-180 to PS/2 adapter is all that's required to connect an AT keyboard to a computer with a PS/2 port. Such adapters can be acquired inexpensively on eBay. But be advised that some motherboards (especially older ones) won't support hot-swapping the keyboard (ie, connecting and disconnecting whilst the PC is turned on) and will require the system to be turned off before the keyboard can be connected and recognised. This is because AT was an interrupt-based standard where the keyboard was treated as an integral component of the PC - some motherboards may still treat the keyboard as such and won't allow hot-swapping, whilst others may instead have an onboard active PS/2 to USB converter that would allow for hot-swapping. If you passively adapt an AT keyboard and connect it through a PS/2 port and it doesn't immediately work, simply try restarting your PC with it connected.

Specific parts & resources

See Further reading & resources for potentially more resources

Using a modular-style terminal keyboard

From 1987 onwards, IBM switched from using DIN-style connectors to modular-style connectors for its terminal keyboards, starting with the IBM 3151 ASCII Display Station and then widely adopted by IBM's InfoWindow Display Stations from 1989 and into the '90s. The 8-pin modular connector is the same type used for RJ-45 and ethernet, although the terms are not interchangeable as "modular" describes the type of connector and RJ-45 and ethernet are two standards that amongst other things make use of the connector. Despite the change from DIN style connectors to modular 8P5C, the protocol used by the keyboards was still IBM scancode set 3.

Converting to USB

Keyboards with this modular plug will not work when plugged into an ethernet port. Since terminal keyboards like the ones that use these were not consumer products, no converter for them can be found in traditional stores or online retailers. It's only during the previous decade that an easily accessible converter appeared - Soarer's Converter, which became and remains the go-to solution. Soarer's Converters can be bought premade from orihalcon's eBay store or you can assemble one yourself. TMK and QMK alternatives to Soarer's Converter exist but have only gained traction relatively recently. They can also be bought premade or assembled yourself.

Specific parts & resources

See Further reading & resources for potentially more resources

Using a PS/2 keyboard

This style of connector was the most common keyboard connector during the decade before USB and continues to be present on some desktop PC motherboards. IBM introduced this connector with its Personal System/2 PC family in 1987, which is also PS/2's namesake. Many PC-compatible IBM Model Ms have modular or fixed cables that end in a PS/2 plug. Despite the physical difference between the two connectors, PS/2 is protocol compatible with the previous AT standard. PS/2 plugs and sockets for keyboard connectivity are typically colour-coded as purple in some way (with mouse connectivity being green).

Using a motherboard's port

Some desktop PC motherboards still retain PS/2 ports, typically in the form of a combined keyboard and mouse port that can operate with one or the other. Model M keyboards and later IBM PS/2 keyboards should work with such ports, but be advised that many motherboards won't support hot-swapping the keyboard (ie, connecting and disconnecting whilst the PC is turned on) and will require the system to be turned off before the keyboard can be connected and recognised. This is because PS/2 was an interrupt-based standard where the keyboard was treated as an integral component of the PC - some motherboards may still treat the keyboard as such and won't allow hot-swapping, whilst others may instead have an onboard active PS/2 to USB converter that would allow for hot-swapping. If you connect a PS/2 keyboard and it doesn't immediately work, simply try restarting your PC with it connected.

Converting to USB

Most IBM and family keyboards that are PS/2 compatible require an active PS/2 to USB converter since a lot of them predate USB, meaning passive adapters are insufficient. Differentiating PS/2 to USB passive adapters and active converters is easy - passive adapters are typically simple-looking devices coloured in purple (keyboard) or green (mouse), whereas active converters usually take the form of a cable with a box in the middle of it containing the IC and more often than not provide both keyboard and mouse ports. The mouse port on such converters can be left unused if your keyboard lacks an integrated pointing device. Some older active converters could also take the form of a blue cube. The Perixx PERIPRO-401 is a well-known active converter that works with Model M keyboards. Specifically in the USA, Monoprice's USB to PS/2 dual PS/2 converter seems to also be common.

If advanced customisation features such as hardware-side (ie, free from constantly running software) layer, macro or remap creation are desired, Soarer's Converter is a well-known 'up market' option. Soarer's Converters can be bought premade from orihalcon's eBay store or you can assemble one yourself. Note that if your keyboard has an integrated pointing device that also uses a PS/2 plug, Soarer's Converter will not support it (although the keyboard itself should still be operable). TMK and QMK alternatives to Soarer's Converter exist but have only gained traction relatively recently. They can also be bought premade or assembled yourself. TMK's IBM PC also supports a secondary PS/2 interface that can be used for converting a PS/2 mouse such as an integrated pointing device on a Model M4-1, M5 or M13 keyboard.

Converting to XT

If connecting a PS/2 keyboard to an XT-class PC such as an IBM 5150 PC or IBM 5160 PC/XT is desired, active converters to allow this exist. Monotech PCs' PS/2 to XT Keyboard Converter and Hagstrom's KE18-ATXT-PS/2 are two known PS/2 to XT keyboard converters. Simple DIN to PS/2 passive adapters will not suffice as XT's set 1 and PS/2's set 2 scancodes are not compatible.

Converting to AT

Since PS/2 and AT are fully compatible with each other, a simple passive adapter is all that's required to connect a PS/2 keyboard to an AT-class computer such as an IBM 5170 PC/AT. Such adapters can be acquired inexpensively on eBay.

Specific parts & resources

See Further reading & resources for potentially more resources

Using a 6-pin SDL keyboard

The 6-pin SDL socket is the most common type of socket used for modular cable connections with Model M keyboards. Whilst they may resemble a modular series connector, they are not compatible with each other. All Model Ms that used SDL sockets support IBM scancode set 2 and thus use some form of SDL to AT or SDL to PS/2 cable. Some early Model Ms such as those for PC/XT and PC/AT may also support IBM scancode set 1, such Model Ms supported both and could switch scancodes via an auto-sensing routine that by default results in AT compatibility. In the 1990s, IBM introduced numerous keyboards with integrated pointing devices that also use SDL but require a specific cable to utilise their mouse component.

My keyboard has no integrated pointing device

Acquiring an SDL to PS/2 cable

As Model Ms with this port are compatible with IBM scancode set 2 (AT and PS/2), getting such a keyboard up and running that's presently missing the cable is a matter of finding the right cable and then acquiring an active converter for it (if you also lack a PS/2 port). Unicomp currently sells a compatible SDL to dual PS/2 cable (P/N 1398094) for $16 USD that should work with any 6-pin SDL Model M. Despite the fact it has a PS/2 plug for a mouse, the cable should still work with a keyboard lacking any integrated pointing device. Alternatively, you may also find SDL to AT or SDL to PS/2 cables second-hand or new-old stock on eBay for varying prices. Such cables can be found by using "Model M SDL to PS/2 cable" as possible search terms. Once such a cable is purchased, the information found in the Using a PS/2 keyboard section is now applicable.

Acquiring an SDL to USB cable

Cables that integrate an active converter into an SDL to USB cable also exist but are subject to low availability, high pricing, and possibly sold only with a minimum order quantity from a wholesaler. orihalcon has previously sold an SDL to USB cable with an integrated Soarer's Converter that would allow hardware-side (ie, free from constantly running software) layer, macro or remap creation if desired.

My keyboard has an integrated pointing device

Acquiring an SDL to dual PS/2 cable

Unfortunately, SDL to USB cable options are not suitable for Model Ms with integrated pointing devices. As such, acquiring an SDL to dual PS/2 cable and a subsequent active converter for it (if you also lack a PS/2 port) is the most practical option. Thankfully, Unicomp currently sells a compatible SDL to dual PS/2 cable (P/N 1398094) for $16 USD that should work with all Model M4-1 and most Model M5-1 and M5-2 keyboards with SDL sockets.

Alternatively, you may also find SDL to dual PS/2 cables second-hand or new-old stock on eBay for varying prices. For raven black Model M4-1s, a black variant of the cable also exists. Such cables can be found by using "Model M SDL to PS/2 cable" as possible search terms. Once such a cable is purchased, the information found in the Using a PS/2 keyboard section is now applicable although note that the Soarer's Converter option mentioned in it doesn't support a second PS/2 interface to connect your keyboard's integrated pointing device through.

Acquiring an SDL to AT DIN & serial DE-9 cable

If you're using a Model M5-1 or M5-2 that's known to use an AT connection for the keyboard and an RS232 serial with a DE-9 connector for the integrated pointing device and you're missing its cable, your options may, unfortunately, be limited. An SDL to AT DIN & serial DE-9 cable indeed exists but Unicomp doesn't presently stock them and thus must be acquired as second-hand or new-old-stock. P/N 1399919 is a known example of such a cable that you can use for your search. If you're unable to find a cable, there are some more options to consider:

Specific parts & resources

See Further reading & resources for potentially more resources

Frequently asked questions

Why does my computer see my converter as barcode or card reader?

Barcode scanners and magnetic stripe readers are commonly available as PS/2 devices. Such devices are known as "keyboard wedges" as they report the scanned data to the computer using keyboard scancodes^[3][3]
TechTarget - What is a keyboard wedge (KBW) [accessed 2024-01-15]. License/note: retrieved via Wayback Machine (2023-12-08 capture).. This seems to be a potential market for active PS/2 to USB converters and is even mentioned as a possible selling point on some converters sold on AliExpress^[4][4]
Enfinity Store @ AliExpress - PS2 USB Adpater,USB Male to PS/2 Female Splitter Mouse Keyboard PS2 Converter Extension Cable,KVM Barcode Scanner PS/2 to USB [accessed 2024-01-15]. License/note: retrieved via Wayback Machine (2024-01-15 capture).. As such, it's possible affected converters report themselves to be a "barcode reader" (etc.) to the host computer so it can be easily identified by software that might want to capture reported keyboard wedge data but ignore other keyboards the computer may have.

Further reading & resources

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External

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