Try to find the IBM/Lenovo's membrane keyboards modeled EKB-425A, SK8813, KB1468.

They're basicly the same keyboards produced by different OEM manufacturers. Standard 104 keys shape, PS/2 interface, good touch feeling, good quality, excellent compatibility!

You'll have nothing to worry about in almost all retro platforms, DOS, Win9x, WinXP...

If you prefer USB interface, there're also a series of USB version, such as SK8815, SK8827...

Regardless of the LED insanity on them, keyboards have to stick to power spec of the ports they work on. So long as your vintage machine is capable of supplying power up to spec to its DIN, PS/2 or USB ports, you should be fine. In fact, power draw on modern keyboards is a lot lower than on old beasts like IBM Model Ms, which have a tendency not to work on boards with flakey power regulation.

I've used a Redragon USB "gaming" keyboard a bunch on various old machines and haven't had issues. And I always leave the backlight on because I'm too lazy to bother turning it off since I'm usually just using it for testing.

This is just my experience though, it'll depend on the keyboard manufacturer and the motherboard/USB card you're using, but you'd probably be fine.

quigonhu wrote on 2024-05-29, 06:37:

Try to find the IBM/Lenovo's membrane keyboards modeled EKB-425A, SK8813, KB1468. […]
Show full quote

Try to find the IBM/Lenovo's membrane keyboards modeled EKB-425A, SK8813, KB1468.

keyboard.JPG

They're basicly the same keyboards produced by different OEM manufacturers. Standard 104 keys shape, PS/2 interface, good touch feeling, good quality, excellent compatibility!

You'll have nothing to worry about in almost all retro platforms, DOS, Win9x, WinXP...

If you prefer USB interface, there're also a series of USB version, such as SK8815, SK8827...

As cool as that thing looks, I'm not sure I want a vintage keyboard because there's a likelihood they would come with some flaw (even if they're sold as "tested and working") or in a state where my OCD would compel me to clean them. A new keyboard is significantly less likely to have either issue.

@rest of thread

Thanks. Hearing that newer keyboards actually drain less power actually fills me with confidence.

I second that these IBM/Lenovo keyboards are great keyboards and usually are dirt cheap (i payed fo couple of these visually like new 5 euro). Little difference on power draw is not important.

I think I've just come up with another project: measure current draw over 5V line on keyboard connector for different keyboards, old and modern. Yay, another interesting thing I don't have time for 😜

dionb wrote on 2024-05-29, 09:04:

I think I've just come up with another project: measure current draw over 5V line on keyboard connector for different keyboards, old and modern. Yay, another interesting thing I don't have time for 😜

That could be extended to KVM switches and other peripherals fed by the PS/2 port aswell. I wouldn't worry too much when plugging in a single keyboard no matter how old it is, but with some KVM switch configurations etc, power draw might become an issue 😀

Im sure most know but a lot of modern USB keyboards dont have any fall back PS2 legacy support any more so can only operate over pure USB assuming the USB being used is capable of delivering the right amount of power and amperage, this means no USB to PS2 adapters. No idea if this affects all modern keyboards, im sure some of the more expensive exotic mechanical ones may still have some legacy PS2 support still.

I guess some research might be worth doing here to see which modern keyboards will work with both USB and a PS2 adapter, same for USB mice though Im not 100% sure they are affected by this, I have a feeling that the more RGB present may cause issues with a PS2 adapter, again I'm not certain because I dont use modern peripherals on retro gear.

Trashbytes wrote on 2024-05-29, 10:22:

Im sure most know but a lot of modern USB keyboards dont have any fall back PS2 legacy support any more so can only operate over pure USB assuming the USB being used is capable of delivering the right amount of power and amperage, this means no USB to PS2 adapters. No idea if this affects all modern keyboards, im sure some of the more expensive exotic mechanical ones may still have some legacy PS2 support still.

I guess some research might be worth doing here to see which modern keyboards will work with both USB and a PS2 adapter, same for USB mice though Im not 100% sure they are affected by this, I have a feeling that the more RGB present may cause issues with a PS2 adapter, again I'm not certain because I dont use modern peripherals on retro gear.

The key word is "USB1.1"

Not only the keyboard, but also the mouse, if the PS/2-USB adapter is going to be functional, the USB device's protocal shouldn't be newer than Ver.1.1.

quigonhu wrote on 2024-05-29, 11:34:

The key word is "USB1.1"

Not only the keyboard, but also the mouse, if the PS/2-USB adapter is going to be functional, the USB device's protocal shouldn't be newer than Ver.1.1.

Whether or not a keyboard/mouse uses USB 1.1 has no bearing on it working with a passive USB->PS/2 adapter.

Chances are very good that any kb/mouse purchased today will still be USB 1.1, because it's cheap to implement and faster speed isn't required (despite what manufacturers of "gaming" peripherals might want you to think). But there's absolutely no guarantee they will be PS2 compatible.

The only incompatibility I've had with keyboards was the other way around.

I was trying to use an old 101 IBM M type on an early Slot A with a 750 iron gate chipset. The FIC SD11 mobo wouldn't post or boot when the old keyboard attached. When I switched to a 104 keyboard from the 90's, the problem went away.

It was a painful troubleshooting process because who suspects the keyboard, right?

jmarsh wrote on 2024-05-29, 12:04:

quigonhu wrote on 2024-05-29, 11:34:

The key word is "USB1.1"

Not only the keyboard, but also the mouse, if the PS/2-USB adapter is going to be functional, the USB device's protocal shouldn't be newer than Ver.1.1.

Whether or not a keyboard/mouse uses USB 1.1 has no bearing on it working with a passive USB->PS/2 adapter.

Chances are very good that any kb/mouse purchased today will still be USB 1.1, because it's cheap to implement and faster speed isn't required (despite what manufacturers of "gaming" peripherals might want you to think). But there's absolutely no guarantee they will be PS2 compatible.

Yeah PS2 legacy support was an additional extra on keyboards that bridged both PS2 and USB, at some point fabs got rid of the legacy PS2 support so modern keyboards no longer work via the adapters. Its a shame really but I cant blame the fabs for dropping it.

jmarsh wrote on 2024-05-29, 12:04:

quigonhu wrote on 2024-05-29, 11:34:

The key word is "USB1.1"

Not only the keyboard, but also the mouse, if the PS/2-USB adapter is going to be functional, the USB device's protocal shouldn't be newer than Ver.1.1.

Whether or not a keyboard/mouse uses USB 1.1 has no bearing on it working with a passive USB->PS/2 adapter.

Chances are very good that any kb/mouse purchased today will still be USB 1.1, because it's cheap to implement and faster speed isn't required (despite what manufacturers of "gaming" peripherals might want you to think). But there's absolutely no guarantee they will be PS2 compatible.

Well, in short answer, no.

Actually the fact is just the opposite. You can hardly purchase the USB1.1 device today, not because cheap thing or not, but the USB1.1 controller is widely NOT produced. That means, today, even the cheapest and simplest new produced USB keyboards, are USB2.0 version in highly possibility. For example, the Logitech K120, it's simple, it's cheap, it's a USB2.0 keyboard.

What I recommend is, if someone wants to fit the PS/2 port especially under the DOS operation, the best way is looking for a PS/2 interface keyboard. Or, looking for a simple USB keyboard which is produced before 2010.

Plus, personally, I'm using the Logitech G1 mouse which I purchased around 2007/08 with a USB-PS/2 adapter quite well.

quigonhu wrote on 2024-05-30, 02:48:

Well, in short answer, no. […]
Show full quote

jmarsh wrote on 2024-05-29, 12:04:

quigonhu wrote on 2024-05-29, 11:34:

The key word is "USB1.1"

Not only the keyboard, but also the mouse, if the PS/2-USB adapter is going to be functional, the USB device's protocal shouldn't be newer than Ver.1.1.

Whether or not a keyboard/mouse uses USB 1.1 has no bearing on it working with a passive USB->PS/2 adapter.

Chances are very good that any kb/mouse purchased today will still be USB 1.1, because it's cheap to implement and faster speed isn't required (despite what manufacturers of "gaming" peripherals might want you to think). But there's absolutely no guarantee they will be PS2 compatible.

Well, in short answer, no.

Actually the fact is just the opposite. You can hardly purchase the USB1.1 device today, not because cheap thing or not, but the USB1.1 controller is widely NOT produced. That means, today, even the cheapest and simplest new produced USB keyboards, are USB2.0 version in highly possibility. For example, the Logitech K120, it's simple, it's cheap, it's a USB2.0 keyboard.

What I recommend is, if someone wants to fit the PS/2 port especially under the DOS operation, the best way is looking for a PS/2 interface keyboard. Or, looking for a simple USB keyboard which is produced before 2010.

USb 2.0 is 1.1 backwards compatible so Im not surprised they dont make USB 1.1 controllers, USB 3.0 is also backwards compatible with USB 2 and 1.1. USB 1.1 is forwards compatible with USB 2 and 3 controllers so im not sure it matter what version of USB a device has it should work just fine in any USB port made after USB 1.0.

USB 1.1, 2 and 3 devices are also meant to be fully backwards compatible with USB 1.0 ports but USB 1.0 had some weird implementations that didn't always stick to the standard so YMMV.

This is all different from if a USB HID keyboard controller has PS2 legacy emulation though.

Worth mentioning that Unicomp still offers traditional keyboards, if you're ok with buckling spring (clicky). At the moment they only have USB due to a component shortage, although they told me they intend to have PS/2 again in the future.

Keyboard ports, by that I mean DIN/Mini DIN, can supply more than enough current for some flashy LEDs. Most motherboards have a 1A keyboard fuse. I've seen some go up to 2.5A before. Back in the day before USB, it was very common for peripherals to tap off the keyboard DIN connector for power.

quigonhu wrote on 2024-05-30, 02:48:

Well, in short answer, no.

Actually the fact is just the opposite. You can hardly purchase the USB1.1 device today, not because cheap thing or not, but the USB1.1 controller is widely NOT produced. That means, today, even the cheapest and simplest new produced USB keyboards, are USB2.0 version in highly possibility. For example, the Logitech K120, it's simple, it's cheap, it's a USB2.0 keyboard.

In short, yes. Here's the device descriptor from your example (the K120):

Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 […]
Show full quote

Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x046d Logitech, Inc.
idProduct 0xc31c Keyboard K120
bcdDevice 64.00
iManufacturer 1
iProduct 2
iSerial 0
bNumConfigurations 1

This is with the device connected to a USB3.0 port, so it's definitely not falling back to USB1.1 just because 2.0 isn't available. It simply isn't a USB2 device, like the majority of keyboards still sold today. They're still using the same basic keypad scan chips (w/ USB1.1 interfaces) they've been using for the past 20+ years because there's no reason to change them.

kaputnik wrote on 2024-05-29, 09:39:

dionb wrote on 2024-05-29, 09:04:

I think I've just come up with another project: measure current draw over 5V line on keyboard connector for different keyboards, old and modern. Yay, another interesting thing I don't have time for 😜

That could be extended to KVM switches and other peripherals fed by the PS/2 port aswell. I wouldn't worry too much when plugging in a single keyboard no matter how old it is, but with some KVM switch configurations etc, power draw might become an issue 😀

KVM switches tend to be powered themselves. I've had the opposite experience - a KVM switch that was extremely flakey with an IBM Model M but worked fine with anything more modern / less thirsty.

dionb wrote on 2024-05-30, 06:02:

kaputnik wrote on 2024-05-29, 09:39:

dionb wrote on 2024-05-29, 09:04:

I think I've just come up with another project: measure current draw over 5V line on keyboard connector for different keyboards, old and modern. Yay, another interesting thing I don't have time for 😜

That could be extended to KVM switches and other peripherals fed by the PS/2 port aswell. I wouldn't worry too much when plugging in a single keyboard no matter how old it is, but with some KVM switch configurations etc, power draw might become an issue 😀

KVM switches tend to be powered themselves. I've had the opposite experience - a KVM switch that was extremely flakey with an IBM Model M but worked fine with anything more modern / less thirsty.

Many (if not most) KVM switches with external PSU have the option be powered by the computer's PS/2 keyboard port aswell. Nice to avoid an additional wall wart when possible, and having the KVM switch powering on/shutting down with the computer(s) when they aren't running 24/7, hence the interest for their consumption 😀