PS/2 numeric keypads as rare as Rocking horse tears

[Faringdon]

Hi,
Do you know where PS/2 numeric keypads are to be found less than £500 each?
Why so rare?

https://il.rsdelivers.com/product/cherry/g84-4700lpbus-2/cherry-black-wired-ps/2-numeric-keypad/4608210

[Nominal Animal]

PS/2 keyboards seem to be rather rare nowadays in general.

How about using an USB numeric keypad, and an USB Female to PS/2 Male (active) adapter?  The active adapters are a bit rare, since many keyboards and mice actually support PS/2 on the USB interface directly, and the "adapter" is basically just a pair of connectors; but they only work if the keyboard/mouse hardware explicitly supports that.  Of course, some of the USB numeric keypads might support such passive adapters; only their datasheets will tell, though.

You could also build the adapter yourself, using say an Arduino Nano or Arduino Pro Mini, and an USB Host Shield for Arduino (based on MAX3421E), for about 10-15 UKP.  For AVR-based Arduinos and MAX3421E-based USB host shields, Oleg Mazurov (felis) maintains USB Host Shield 2.0 Arduino library at github; for the PS/2 device side, Tomas Mudrunka (Harvie) maintains ps2dev Arduino library at github.

The PS/2 connector has 5V signal levels, and can provide up to 275mA at 5V (per spec).  Arduino Pro Mini will consume under 15mA, and an Arduino Nano under 25mA, so there should be no problem powering an USB keypad from this source (but I recommend you check the peak current use of whatever device you use; a cheap USB power meter should be good enough for this).

I like the adapter approach, because you can 3D print a small inline cable box (oval or bicone) to contain the adapter, and use with any USB numeric keypad.  Might make a nice hobby project by itself, too.  It might even be worth it to create a tiny Arduino Pro Mini clone with just a MAX3421E, and directly solder an USB cable to the MAX3421E (with a female connector) and an PS/2 cable (with a male connector), shaped so that it fits in an inline enclosure; as an OSHW USB-Keyboard/Mouse-to-PS/2 adapter.  (As of 2021-08-12, JLCPCB SMT service has MAX3421EEHJ+ (part C45862) and ATmega328P-AU (C14877) and ATmega328PB-AU (C132230) in stock, so one could even get the boards manufactured and soldered using the JLCPCB SMT service.)

[TimFox]

A quick search found one on Amazon for $14.95 USD:  https://www.amazon.com/HP-Windows-Keyboard-672646-003-724718-001/dp/B079YM1WH3/ref=asc_df_B079YM1WH3/?tag=hyprod-20&linkCode=df0&hvadid=524643816709&hvpos=&hvnetw=g&hvrand=5092947563564549167&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9021734&hvtargid=pla-1387192437274&psc=1

[hexreader]

@treez

Instead of buying from RS Israel for 500 New Shekels (£112)...

... buy from RS UK for £56-50 + VAT + postage

[TimFox]

Oops-  that Amazon link was for a PS/2 full keyboard.  Numeric ones on Amazon cost $12.50 USD.

[ebastler]

Oops-  that Amazon link was for a PS/2 full keyboard.  Numeric ones on Amazon cost $12.50 USD.

Would you have a link? All the cheap stuff I see has a USB interface, not PS/2.

[BrokenYugo]

They're going to be NOS or low production, either way the main demand will be from businesses with legacy equipment who probably lose more than that an hour if they're short one, so they'll pay.

[Ian.M]

It helps to use the correct better search terms.  e.g. Google: "PS/2" PoS number pad

PS/2 standalone number pads are rare like rocking horse sh!t because nearly all PCs with 'legacy' ports only had a single keyboard port (a very few had two autosensing PS/2 keyboard/mouse ports), so their *ONLY* applications were point of sale and similar uses where you don't want the muppet operator to have a full keyboard, and accountants to connect to their luggables.

[Nominal Animal]

A bit of ebay.co.uk searching ("ps/2" "keypad", UK only) does reveal an UK seller for Accuratus 100 numeric keypads with PS/2 connector with 100% feedback over 2495 sales at a very reasonable price (NOS, old model, I believe), as of 2021-08-16.

It might be worth it to throw an email at ceratech.co.uk to ask whether the current version of this numpad is dual USB-PS/2, i.e. supports PS/2 via a passive keyboard connector converter, seeing they sell those new for 22 UKP + VAT, and looks like it might be more comfortable to use.

[johnboxall]

https://www.aliexpress.com/item/32711349699.html