Keyboard QnA

I have gathered a list of questions people may have about IBM and co keyboards and have attempted to answer them. These range from questions beginners in the keyboard hobby may have, what prospective IBM and co keyboard buyers may want to know, and even some research-style technical questions. Some of these may have subjective answers, so please don't be surprised if other people or websites answer them differently.

Are Model Ms "mechanical" keyboards?
Unfortunately, the answer is complicated due to two reasons; the Model M is a huge family of different types of keyboards, and the fact that the definition for "mechanical" is not properly defined. Assuming the Model M in question is a standard IBM Enhanced Keyboard, based on common points that people define by; they could be mechanical since they have part-way actuation, use a coil spring of some sort and are simply not rubber dome switches, but they could also not be mechanical due to the membrane sensing circuit and the fact it does not have NKRO. In reality, "mechanical" is a non-standard marketing term with a loose definition that is based on the subjective opinions of enthusiasts, meaning using the term is only really useful for insinuating a high-end keyboard - which Model Ms were and are still today - regardless of most of its technical specifications. Anyway, membrane and NKRO points could be rebutted too - compared to the Model F's capacitive buckling spring, the sensing circuit is the only major design difference but how the switch works, clicks, and provides feedback is still exactly the same. Also, what stops people from arguing that the limitation of the USB interface on some other keyboards downgrades them to non-mechanical because they can only reach 6 to 10 KRO?
Can I use Model Ms for gaming?
Absolutely, with some considerating in mind. Model Ms have the reputation of being more of a typing instrument than a gaming peripheral due to 2KRO and high actuation force requirement. Starting with 2KRO, in practice, 3 or 4 simultaneous keystrokes will be registered depending on the location of all the keys being pressed - for example, if you were playing a first-person shooter game, you can press W+A or W+D to move, press G to throw a grenade, and press a modifier key together and all will be registered. Secondly, it is true that the required force can be an issue for people used to light switches and thus could tiresome people's fingers when rapid pressing is required in a game, so consider buying a membrane buckling springs key switch tester if this is a concern to you before buying a Model M keyboard outright.
How much should I be concerned about failing plastic rivets on a Model M?
On average, it should not be a huge concern since plenty of people buy and sell Model Ms that have yet to be bolt-modded and never experience issues after long transits. For brand new Unicomp Model Ms, you probably will not have any such issue for at least a decade provided you take good care of it. The most likely Model Ms to be suffering such catastrophic plastic rivet failure are ones that are so old that the plastic itself is being to degrade, those that come from industrial use, and those that come from areas of the world with inhospitable climates.
I want to use my vintage PS/2 keyboard with a modern PC - how?
Converters for PS/2 to USB keyboards are plentiful, but you will need to be vigilant in regards to the type you need. Both passive adapters and active converters exist, with passive adapters simply being a pin swap between the two types of connectors for more modern PS/2 keyboards that also support USB protocol internally. Your '80s Model M, for example, cannot do this, so what you need is an active converter. As a rule of thumb, active converters are specifically labelled as such, sometimes described as having a USB integrated controller (IC), feature a small box in the middle of the cable, and more often than not include both keyboard and mouse PS/2 ports together. Exceptions to this exist, however, so be sure to check out reviews and ask the manufacturer to clarify.
Was there any official distinction between the IBM 6580 Displaywriter System's beam spring and Model F keyboard variants?
Yes! The beam spring keyboard is known as Type A and the Model F keyboard is known as Type B. The February 1983 revision of the IBM Displaywriter System Product Support Manual describes these terms on Chapter 5 (Keyboard), specifically on page 64 of the bitsavers' PDF scan of this document. Figures showing the Type A and Type B assemblies are visible on page 63 (Figure 5-1) and page 64 (Figure 5-2) respectively.
What do the 'a with caret/chevron' and 'a/aaa with cross-out' keys on Model F104, F122 and early M122 keyboards do?
For the keyboards' original terminal layout, the 'a with caret/chevron' key functions as an insert key and 'a/aaa with cross-out' functions as a delete key. Evidence for this can be found by examining the Model F-based IBM 3270 PC Keyboard Element (such as P/N 6110344) - specifically, by comparing the physical layout (credit to John Elliott) with a known functional layout diagram (credit to John J. G. Savard).
What screwdriver do I use to open up my Model M with?
For mainstream buckling springs and Quiet Touch Model Ms, you are looking for a 5.5mm (7/32") nut driver. They can be had for just under £5 off eBay as of 2020. They are typically sold as being for Vruzend battery kits and for bicycles.
What's the difference between a passive adapter and an active converter?
The key is in the noun that passive or active is paired with. Whilst many may use the words adapter and converter interchangeably, there is a technical difference and the best way to look at it is as follows: an adapter adapts between two or more given physical interfaces, and a converter converts a between two or more given signals and possibly adapts the physical interface at the same time. With this in mind, a passive adapter simply changes one physical interface to another without modifying the electrical signals - for example, an AT to PS/2 adapter would be considered passive since both use the same underlying protocol and only the physical connectors are different. By contrast, an active converter processes the data running between the keyboard and host computer with an integrated circuit for the purpose of transforming one protocol into another - for example, a Soarer's Converter would be considered active since it converts the Set 1/XT, Set 2/AT or Set 3/terminal scancodes of the keyboard into USB HID scancodes.
Which are better - Model Fs or (buckling springs) Model Ms?
Starting with core technology, the Model F's capacitive buckling springs have the chief benefits of inherent NKRO and a much higher expected lifetime. Subjectively, people may prefer the high-pitched auditory feedback and lighter feel of capacitive buckling springs too. Although, the exact opposite is possible too. Moving to construction quality and technique, both families score well in different aspects. Model Fs are known for been made of harder (but also more brittle) plastics or alternatively metal. This makes Model Fs feel and seem more robust when touched/held. However, Model Ms are usually made of more flexible plastic that whilst doesn't feel as taut as Model F plastics can absorb more damage without cracking. Both families have a major Achilles' heel, however; over time, Model F assemblies are prone to foam degradation and Model Ms are prone to plastic rivet loss. Both can be mitigated with new foam or a bolt mod, at least. In terms of usability and familiarity, Model Ms take a clear win. The 101/102-key Enhanced Keyboard Model M standardised the ANSI and ISO layouts we currently use, making them far more familiar than XT or AT Model Fs. Various terminal Model Fs can have more familiar layouts, but this comes at the price of them using protocols not natively PC compatible. Most Model Ms are either AT or USB HID compatible, allowing them to be easily used with modern PCs with at most a cheap active converter from Amazon for PS/2 Model Ms. Until the advent of Soarer's Converters, only the Model F/ATs could be easily used on modern PCs. Speaking of which, the Model F/AT is the only Model F with lock-light LEDs, whereas most AT, PS/2 and USB Model Ms have them, which could be seen as an advantage in favour of Model Ms to some. In summary, Model Fs are technically better whereas Model Ms are practically better.