The passive aggression of connecting USB to PS/2 Before Bluetooth and USB, computers had PS/2 ports. Microsoft veteran Raymond Chen took another trip down memory lane this week to explain just how dumb the USB-to-PS/2 adapters that shipped with Microsoft Mouse devices really were. The Microsoft Mouse first shipped in 1983 with a DB-25 serial connector. This was later updated …
Last night, I opened up a non-techie friend's Windows PC to replace a dead fan. It had a Bluetooth KB. After I closed it back up, reconnected everything and powered it up, I was greeted by an ASUS BIOS message: "Press F2 for Setup or Enter to continue."
I pressed [Enter] ... nothing happened. [Enter]. Nothing. [Enter][Enter][Enter][Enter]. Nothing.
"Aurora, do you have a wired keyboard somewhere?"
"No, I gave it away."
KB batteries were good (she'd been using w/o problem before I arrived), and I'd not disturbed the BT dongle in one of the PC's USB ports.
<Reboot> very long wait. "Press F2 or ..." [F2]. BIOS SETUP (with GUI) appears. I clicked [Exit without saving changes]. VERY long wait, then the Windows blue-window logo appears. VERY long wait with the Windows spinning beads, then the Windows GUI appeared.
There are two USB keyboard profiles, the normal one and the boot one. The main distinguishing point is the boot profile only sends up to 6 keys at once whereas the normal profile sends as many or as few keys as the keyboard wants (and was thought overly complex for BIOSes to implement).
In theory both profiles can be sent at once although some keyboards don't do that, some BIOSes don't specifically ask for the boot profile so the keyboard sends just the normal profile, and other BIOSes can't deal with receiving both profiles at the same time and parsing just the boot profile although they should be able to.
If your keyboard has a key combo to disable NKRO or enable 6KRO then the BIOS might suddenly start responding to the keyboard.
My work PC, a year or so old Dell Precision workstation has one. I also rebuilt my home office PC a few months ago with all current tech, and it too has a PS/2 port.
And I USE them, one of the reasons I picked the MB that I did was because of the PS/2 port, as I use IBM Model M's at work and at home.
I think the hard core gamer types like PS/2 because of better latency numbers... but you'd have to talk to someone who really cared about such things to know for sure.
For wireless keyboards and mice that have a USB dongle, the dongle looks to the system like a USB hub with a USB keyboard and mouse attached. The system is completely unaware of the devices being wireless. Although the wireless protocol in these devices often use Bluetooth hardware, most do not use the Bluetooth software protocols (and thus can't be used with the built-in Bluetooth support that many systems now have). Proper Bluetooth devices are, of course, different.
But I sometimes use old systems (often HP ex. Windows terminals that I redeploy as low-power, always on Linux servers) that do not by default enable USB in the BIOS during startup. When you come across one of these systems set to default, it is impossible to use a USB keyboard to enter setup to change the default to enable the USB during startup.
Of course, changing this default setting allows you to use USB keyboards, but it's very much a chicken-and-egg situation. And you have to remember to not set the BIOS back to factory defaults!
As a result, I always keep a keyboard with a PS/2 connector around somewhere. The main one (that I will never get rid of unless it fails) is my IBM Model M.
Also, cue the historical "Keyboard error, press F1 to continue" message that always amused me!
Also, cue the historical "Keyboard error, press F1 to continue" message that always amused me!
Its amusing because most people who see it are deliberately trying to run without a keyboard, but it is assuming that you want a keyboard to keep going, so its waiting here so you can attach one and press F1 to confirm that a keyboard has been attached so it can continue. From that POV, the error message is entirely logical!
It's even more logical, as from memory if you booted without a keyboard into Windows for example, subsequently plugging a keyboard in once the system was up and running wouldn't be recognised and so there was no way to shut the machine down other than pulling the plug, and old systems didn't particularly cope well with that. The message was really saying "you've not plugged in a keyboard... sure you wanna do that?.."
If you wanted to run the machine headless, switching the error off in the BIOS was the way forward.
"so its waiting here so you can attach one and press F1 to confirm that a keyboard has been attached so it can continue. From that POV, the error message is entirely logical!"
Except that error is still present on PCs with PS/2 keyboards and it's really recommended to plug it in after the PC is turned on. Mostly because most PCs only recognise the k/b only if it's already plugged in at power on and ignores it if you plug in later, but also because it could blow the k/b fuse on the motherboard. But, as mentioned by others, this error can mostly be disabled on "modern" BIOS configs.
Irn Bru or Tizer (never got to the bottom of which one it was, the kids wouldn't own up to who did it, but it was orange and sticky) definitely killed one of my model Ms. IBM did not pot a sealing bead on the membrane of their Model Ms (Unicomp do now), so liquid ingress was possible, It dissolved the tracks on the membrane, and more got pulled off when trying to peel it apart to repair the tracks. Whether throwing it in the dish washer before trying a repair would have helped, I will never know.
I've also had a Unicomp one fail as a result to Coke being spilled on it for similar reasons (don't know how it got past the sealing bead, but it did), but at least I could get a replacement membrane shipped to repair it.
I've also had the control board of a USB Unicomp one fail as well.
Model Ms are not indestructible. But they can be very long lived if treated right.
I often whether the non-contact Model F keyboards with the capacitive sensors would have lasted even longer, but I suspect that most of those were scrapped because they had the 5 pin DIN and PC/XT protocols that made them difficult to use on later PCs (plus they were, by today's standards, a very strange layout). They did feel amazing to type on, however.
The keyboard error actually dates back to the original behavior of the A20 gate on 32/16-bit x86 processors where the gate (which switched between 8086 emulated mode and 80286 style high memory mode) was controlled by the keyboard controller. Hence you had to connect a keyboard and press F1 to let the BIOS know there is a working keyboard to operate the gate.
It was a very hacky method which later moved inside the processor silicon before apparently becoming entirely removed (though some sources just say it no longer has a physical A20 gate output but still emulates it).
Yeah, Bluetooth requires a stack, and it's not available pre operating system boot.
There are a very small set of Bluetooth dongles that do a USB proxy[1] so they will work on boot, but they tend to be a bit variable in quality, and quite uncommon.
I do have one here and will be trying to get it working with a HIDMan, and a small USB keyboard and trackpad.
The problem then is there are *no* decent USB keyboards and trackpads in one device regardless of how much you offer to pay. The cheap Chinese clones don't support Boot Mode properly, so they need hacks to make them work. Logitech/Microsoft - please create a decent, small (holdable in one hand), rechargeable Bluetooth keyboard with integrated trackpad, and all function keys. I'm willing to pay up to a 100 quid for it, possibly more if the quality is persuasive.
[1] one end looks like a USB keyboard, the other end does the Bluetooth stack and pairing to the keyboard/mouse. One problem here is often the dongle has no method of typing in a pairing key, so it needs to work without one, even further reducing the choice of devices
Maybe something I can build with a Zero W v1.2, plus this already supports Bluetooth and can possibly be programmed to connect with existing found dongles using its own USB port.
One idea would be to have it contain a user replaceable touchpad, keys that if they do break can simply be replaced and multi-function function keys with actual micro-projectors that can be set underneath so if you want one button to do Ctrl-Alt-Del or the Mac 'Vulcan Nerve Pinch' then it can. For added bonus points the battery is replicated so it has a main and backup battery that are fully independent so if one goes bad then it switches to the other seamlessly. Macro function obviously, support for minimal video so you can use it with a headless SFF or similar.
One of the reasons to keep a PS/2 port around is for interrupted signalling, something USB can't do. USB needs to do polling, be it 200Hz, 500Hz... so they invented a way for USB to do interrupts too, via software, so no keyboard gets any perceived lag.
Another is keyboard rollover or NKRO: you can press as many keys at once you want, the system will get them all with ps2 signalling. USB keyboards had to add smarts to allow NKRO.
A third reason are BIOSes that don't support usb keyboards... but these are vintage now.
So, if you got a ps2 port and means to use it, slap the keyboard on it. Otherwise, any difference is merely academical.
Mice never had that problem, because they were already built after USB.
The first mouse I owned had a 9-pin serial connection, with a 9-25 way adaptor in case your PC still had the full-fat RS232 connector. That was the classic Logitech C7 3-button mouse from the mid-80s.
However before USB, before PS2, before RS232 for mice was standardised, mouse history also includes Bus Mice which needed their own ISA card to connect them into a PC.
Of course, various non-IBM PC computers, had their own proprietary mouse interfaces too.
The first mouse I owned (and still have...) had the raw quadrature outputs from the shaft encoders as it's interface. I had to build (from TTL parts) a circuit to generate a movement interrupt and a direction flag for each axis, and write a "driver" for it. In Z80 assembler.
Now where's my chisel...
"However before USB, before PS2, before RS232 for mice was standardised, mouse history also includes Bus Mice which needed their own ISA card to connect them into a PC."
Yup - I remember buying a mouse for a pre-Windows 3.x 286 PC I had on which the motherboard only had one 9-pin serial port (which I needed to connect to a modem) and one 25-pin parallel port for my printer. So, to add a mouse, I had to find a suitable one that came with it's own 8-bit ISA bus adaptor card. (The mouse was needed to help quickly navigate various menu options in both a DOS-based graphics program (rather than using keystroke combinations) as well as to use with various comms programs, such as ProComm+).
Nowadays, people are lucky as most PC motherboard have got multiple USB 2.0/3.0 connectors, network ports, 3.5mm audio sockets, TosLink optical outputs, lots of PCI slots, SATA and maybe eSATA sockets, and many graphics cards have multiple HDMI and Displayport sockets.
I installed my fair share of mouse adaptor cards at work in the late 80s and early 90s, but the first mouse I bought for myself was a 2-button wired Kempston Mouse for my ZX Spectrum. It had tiny ball bearings at each corner instead of the now ubiquitous low friction pads, so not only did it have ears and a tail, it actually squeaked when you pushed it around.
I can't parse your last sentence, but can say that mice probably never had that problem because the mouse/cursor freezing is considered normal behaviour on a computer and it's not expected to "catch up", whereas with keyboards people may well continue typing and trust that the words eventually appear.
> So, if you got a ps2 port and means to use it, slap the keyboard on it. Otherwise, any difference is merely academical.
Only do this if the machine is powered off.
PS/2 ports are notorious for not liking things plugged in (or removed) when they were powered on.
I've managed to ruin a few PS/2 ports by just swapping out a dead keyboard (users eating tangerines at their desk whilst typing ...) and too late remembering that the machine was not powered off yet. Giving a whole new meaning to the HOT in hot swapping.
Fortunately those machines also had USB ports.
The last time i encountered a PC that did not support USB in the BIOS must have been around the turn of the millenium (though I've kept a PS/2 keyboid/mouse around for another 2 decades orso).
Are you sure it wasn't the tangerines that killed the port? I've swapped many many PS/2 keyboards live and never had a problem beyond a few errant characters (following appropriate grounding protocols, naturally)
Admittedly not had to do it for a good 10 years now though.
There was a behaviour / electrical problem in the design, a capacitor at the wrong place without a tiny resistor to limit its maximum current draw and deliver. You could indeed fry PS2 ports that way. Later computers did not show that issue, but it took way too many years.
I had a 486 IBM PS/1 back in the day. On those machines it was very possible to kill a PS/2 port by plugging in something when the power was on. I knew this and was super careful (although I probably did do it a few times by mistake), but I was working in Dixons over the uni holidays and we did see a fair few come back with this issue. The engineers told me it was a tiny surface mount component that would blow. A capacitor if my memory serves me correctly (although it is 30+ years ago, so I could be wrong).
It was a long time since I used a PS/2 port, and I don't remember any failing, but it does strike me as poor engineering if you could break the electronics with an accidental tug of the cable. As I remember it the mini-DINs relied on friction to stay in, and didn't have a locking tab.
"t was a long time since I used a PS/2 port, and I don't remember any failing, but it does strike me as poor engineering if you could break the electronics with an accidental tug of the cable."
I don't think it was a problem if a PS/2 device was unplugged (accidentally or otherwise ;-) ). But woe betide you, if you plugged it back in, while the PC was still running...
On later PCs with PS/2 ports, the ports were protected by soft (self-healing) fuses; they'd still almost invariably "trip" if a keyboard or mouse was plugged in live, and the PC would still need to be power-cycled to recognize the device, but no permanent damage would be done.
Also, the article states: "The color-coded sockets – purple for keyboards and green for mice – featured on IBM Personal System/2 computers and swiftly spread throughout the PC world..."
which isn't quite correct. The original PS/2 ports were non-coloured; it wasn't until a Microsoft/Intel initiative in the late 90s - PC Design Guide, or "PC'97", and subsequent revisions - after the IBM PS/2 PC era, that the colour codes were introduced (or at least, standardized; some manufacturers had begun using their own colours before then) to make PS/2 ports more user-friendly. I have direct knowledge of this because a close colleague was on the PC'97 working group at the time!
I heard that PS/2 ports were unbuffered and i have seen a couple of dead ports, but mostly I remember that dread of realising I'd connected or disconnected while hot and not knowing if I'd blown it... Or more often, watched a customer do it in front of me before I could stop them.
How so annoying it was whenever I remembered the keyboard or mouse wasn't connected when I turned on a machine that took minutes to boot up and shut down again.
NKRO support depends on the keyboard, Model M and the equivalent Unicomp models are limited to 2 key rollover. Quite a few Northgate Omnikey models do support proper NKRO though.
The ability to hot plug USB keyboards is really useful, particularly to use multiple keyboard layouts. PS/2 has its uses, particularly for use with KVMs, and there's cable distance advantages too (although USB extenders would probably achieve the same thing), but for most purposes these days USB (with suitable adapters for older systems) is a better alternative.
I would note one rather niche case is USB bandwidth and latency. As anyone with an older VR headset and USB base stations will know, it takes a lot of fiddling to get everything working (I was daft enough to get an Oculus Rift CV1 with four sensors working). Even if there is *technically* enough bandwidth for all the devices, adding any other device to the long list of USB connected devices can upset all of them.
(the reliable way to make that work is for each port to have a dedicated controller and bandwidth, but those cards go for 150 quid plus for four ports)
I had loads of these green and purple adapters at work, the collection grew as more and more PCs came with enough USB ports to cope with two being needed for keyboards and mice permanently and the PS2 ports disappearing from motherboards. I still find the odd one of them at home and can instantly tell what it is and what it is for by colour and shape alone, we got some things right in this industry in those old days.
Kids today don't know they're born with their bluetooth this, M365 that... I had to get up early, wade through the SCSI mines, fend off zip drives and floppies just to get to a login screen
I stand corrected.
I've just put my 1990 1391406 model M on the bathroom scales, and with the coiled cable it's exactly 2.15 kg (although the cable contributes quite a lot to the overall weight).
In my defence, the ones I've been dealing with more recently have been Unicomp model Ms, and the backplate as well as the plastics are much lighter.
The 3279 keyboards were something else, however.
For my sins, I was once (when I was young) an IBM field engineer in Londinium. I spent my life repairing 3278/3279 keyboards. Weight wasn't the issue. It was all the crud and detritus that got inside, preventing keys from working. A special hatred for those that smoked a lot and ate their lunch at their desk.......
I've got a modern "Das Keyboard" which is about 1.5kg, mostly coming from the solid aluminium base. It really does feel like you could fend off zombies with it.
"Using a 2.5 kg keyboard as a sword..."
My first PC came with a heavy Cherry Extended (PC-AT) keyboard and it had a huge thick metal plate on the underside...and that keyboard worked for many years, even though the PC was upgraded and then replaced at least two other times. The keyboard used a large round DIN style connector that was plugged into a matching DIN socket, not one of those small pansy purple PS/2 types...
"Kids today don't know they're born with their bluetooth this, M365 that."
Just show some of the kids the 3 different connectors on 1980's hard drives: MFM, RLL and SCSI...and then show them some PC motherboards that don't have the right on-board connectors for these drives and then give them a box of mixed ribbon cables, 4 pin Molex adaptors and various HDD adaptor cards and get them to connect the drives correctly and then get them to install DOS (from a 5 1/4" floppy) onto a working drive and to then boot the computer. !!!!
> the 3 different connectors on 1980's hard drives: MFM, RLL and SCSI...
MFM and RLL used the exact same connectors.
In PC/XT days though, the PC had no HDD code, the *controllers* had ROM code to low-level format and map defects. My memory fails but something like DEBUG -G=C800:5. https://retrocmp.de/ctrl/llf/llf.htm
I grant that SCSI eventually grew way too many connectors.
DEBUG -G=C800:5
That is correct. For some (most?) values of correct. I did come across at least one brand of 8-bit RLL card that used a different offset, possibly 6 or 8. Only the 5 sticks in my memory too since that was most of the ones I came across. Although the - is incorrect. the G was the Go command and didn't have a leading dash. You may be confusing running debug with a command and just typing debug on its own, getting the "-" prompt and then typing the G=C800:5 there.
But yeah, you’re showing both your age and the sort of stuff you did back then! I bet most of us of that era who built/repaired/maintained or just liked "playing" with PCs have that debug command and address etched in our psyche :-)
debug, G=C800:5 works with 8-bit WD controllers (and clones), and most (not all!) WD or Seagate ST-506 type drives (and clones). What it does is run a low-level format utility that is built into the drive controller. 16-bit controllers brought us disk based low level format tools. Note that the Seagate ST-01 and -02 drive controllers were actually made by Western Digital.
Other addresses that might work are G=CA00:5, G=CC00:5 or G=CE00:5 ... check the jumpers on your particular card. If no pins are selected, they usually default to C800:5
This info is long out of date, and only useful to folks who are restoring old kit. You should not attempt it unless you know exactly what you are doing. I have seen this brick a couple of Maxtor 80 Meg IDE drive (no idea why), so don't just run it blindly. The results of running the command blindly on random hardware are undefined, and apt to do anything.
This post should give you more than enough info to DDG for more. Please educate yourself before ignorantly jumping in and breaking old kit needlessly. Ta.
All disclaimers aside, I suspect modern drives will just ignore it.
For people playing with old DEC kit, the easiest way I know to format a MFM drive for use with the RQDX series is to use the ROM formatter built into the VS2000. See http://vaxarchive.org/hardware/vs2000/ for more. Good luck finding a VS2000 ...
Also a useful link: http://vaxarchive.org/hardware/vs2000/fmtbob.html
"Just show some of the kids the 3 different connectors on 1980's hard drives: MFM, RLL and SCSI"
MFM/RLL was just the encoding type used in ST506/ST412 drives. ESDI used the exact same cables, but is a different standard. Let's include ATA (IDE) as the third cable standard.
You're also skipping the fun part where you need to select the correct drive type from the list of standard AT BIOS hard disk types - and what to do if your drive is not listed but your BIOS is modern enough to accept custom drive geometry. You also need to guess the proper Landing Zone and Write Precomp values which were not written on top of HDD.
Also ask the kids to low level format the drive first with optimal interleaving and to type in the bad sectors.
OK, now you triggered a memory here... EZ-Drive, a tool to make DOS recognize a disk larger than 504 MB if the BIOS cannot do it. OnTrack Diskmanager could do the same.
> I still find the odd one of them at home and can instantly tell what it is and what it is for by colour and shape alone
Does anyone make USB mice and keyboards with green and purple plugs? It would be so much easier to figure out which peripheral you're unplugging by looking at the colour instead of having to trace the cable, but for some reason seemingly every single manufacturer decided to switch to black plugs when they moved from PS/2 to USB. Well, apart from Apple, who started with semi-transparent and then eventually settled on white.
COLORED HEAT SHRINK TO THE RESCUE!
By the united power of our colors, we will end the USB chaos!
Available on A, A and A (baba / press / zon). Sorry, the 'zon denied an internationally available search, it refuses to since I am in the evil evil evil Germany/Europe location and I am too lazy to use a VPN just for that... The 'press seems to have the greatest variety anyway...
Trying to tell KVM/QEmu to capture the mouse/keyboard device and pass it between host & guest requires[1] putting the USB-enumeration-generated device id into the XML config. So moving ports, or (far) worse having a glitch during a session and you've just lost the connection (and has it gone to the host, the guest - or is just flapping in the wind?)
[1] in the docs & examples I've found so far; pointers to better ways to do things gratefully accepted.
People seldom know the "E" is there for the shell size (as is the "B") , so a DB-9 connector would be a large shell (like a DB-25) but with only 9 pins sticking out (or holes, for a female socket)
The size order being, from smaller to larger, E-->A-->B-->C-->D, makes it seem like the E shell was a later addition to the standard
...similarly explains why similarly passive PS/2 to USB adaptors- i.e. the other way round- don't always work. Apparently, whatever's controlling the USB port you have it indirectly plugged into still has to be able to detect and handle the PS/2 protocol correctly (*) and this isn't universal.
For example, the USB KVM I use at work doesn't support the old PS/2 keyboard I liked which worked fine on the ancient KVM with native PS/2 ports I used before.
(*) I used to wonder how this was done, as the only way I could imagine was that USB somehow included backward-compatibility support for the PS/2 protocol as standard. Well, apparently some did, but not as standard, but it explained why it didn't work with the newer KVM.
In the early "AT" PC days, keyboards used a large 9-pin DIN connector.
When mice came along, they plugged into the RS-232 serial ports.
IBM released the PS/2 to try to kill off the clone manufacturers and take back control of the PC standard. They failed miserably, but one thing that stuck was PS/2 keyboard mouse ports, which began appearing on newer PCs. Kind of a shame if you ask me. Serial/com ports were useful for mice and a lot of other purposes (still around today at least in USB adapter form), while PS/2 mouse ports weren't useful for anything else and just died off once USB took over.
For keyboards this was no big deal. A cheap adapter converting the large 9-pin DIN to a smaller PS/2 connector worked great. Newer keyboards switched to PS/2 with adapters back to large AT DIN.
For mice, though, this was a real problem. For years, mice came with PS/2 connectors and a PS/2 to DE-9 adapter. The two protocols were different, so mice chipsets implemented both protocols for compatibility.
One footnote here is combo PS/2 keyboard/mouse ports. Saved hardly any physical space, but first laptops, and much later desktops after USB took over, only included a single PS/2 port for both. A mouse could be plugged-in directly, but a PS/2 splitter was needed to plug in a keyboard, or both keyboard and mouse. That wasn't noted on the ports, and many people were confused when plugging in their keyboard didn't work.
This was pretty much standard until USB came out. Nobody wanted to implement two levels of compatibility, so mice dropped RS-232 and instead implemented PS/2 and USB. As did keyboards.
Even if adapters weren't included, PS/2 support stayed around in the chipsets for well over a decade. Go back a few years, and there's a good chance your old keyboard will speak PS/2 if connected through an adapter... Doesn't matter whether green or purple, the adapters were the same for keyboards and mice.
And things like the trackpoint stayed as PS/2 devices way longer than you'd expect, before finally making the jump.
These days PS/2 compatibility is long gone.
I'm disappointed USB hubs in monitors didn't become standard. You've got to plug in a keyboard and mouse, and maybe more. You're always going to be using them near your monitor. Why not include a cheap hub and make it just one USB cable back to your PC? Makes things tidier. But it seems only Dell were convinced it was a good idea. You could always mount your own to your monitor stand. And of course these days wireless input devices are pretty common.
> These days PS/2 compatibility is long gone.
Well, no. You can buy current PCs with current tech still having PS/2 integrated. PoS, in this case Point of Sale/Service, which use custom made and mapped Keyboards. In many cases today it is a built-in USB-PS/2 chip. But they are finally a dying breed win 2025...
I meant it the other way around... Keyboards no longer have PS/2 backwards compatibility included, and haven't for more than a decade now.
One other footnote is that PS/2 offered 5V output at higher-current than USB. I had a 2.5" USB/firewire hard drive with a PS/2 pass-thru adapter with a barrel plug coming out of it to power the portable drive, which was necessary, as mine wouldn't spin-up just from the power of a USB1.1/2.0 port and needed the boost. Firewire supplied more power, but wasn't very commonly available.
You mentioned POS... This extra power was also helpful for "keyboard wedge" barcode scanners, which wouldn't work over USB to PS/2 adapters, unless provided with extra DC input supply.
They're still available in various business monitors. The Samsung S60UA monitor here can, in theory, do everything for your laptop with one USB-C cable. Charge the laptop, display not just on the monitor, but with an addition of the Displayport out port and a Displayport hub, drive more monitors (the Samsung and two other monitors here!), provide network connectivity via the RJ45 port, and link via the USB A hub to your keyboard and mouse (I use it for a webcam).
Unfortunately the firmware is utter and complete cack, and has never had an update. Do Not Buy Samsung for monitors, they don't care. Pity really, because if they fixed the firmware it'd be great. I can work around its issues, but it really is very, very annoying at times.
There's a similar monitor from iiyama I've not had chance to check out yet, but could be decent.
Got a model number? Wouldn't mind taking a look - particularly if the firmware actually works! Ideally it should handle input switching properly, and it shouldn't (as the 60UA does) be merrily working 'ok' displaying one output with two external monitors from the DisplayPort out, and then the moment you turn on a different computer attached to another output it blanks the external monitors connected by DisplayPort out.
(or the fact the 60UA as shipped turns itself off after six hours of active use. or that if it goes into suspend it drops the network connection, instead of turning the monitor display off, but keeping its built in network connection on)
@Peter Kay - Got a model number?
Not the OP, but I have a nice Philips UWS that acts as a decent KVM switch between two laptops [USBC K+V+M] and [DP with USB K & M]:
Philips 499P9H- 49 Inch Curved Dual QHD Monitor
https://www.amazon.co.uk/dp/B07MY2DXPH
(It also has a pop-up webcam, but it's crap)
"And things like the trackpoint stayed as PS/2 devices way longer than you'd expect, before finally making the jump."
Some laptop trackpads do still identify as PS/2. Whether they are running over USB internally or are just identified that way in the driver or are actually PS/2, I couldn't say.
I backed the ZX Spectrum Next on Kickstarter a few years ago, and when it arrived, with its PS/2 mouse support, I had to search through my box of old stuff to find a mouse that would fit it. I found not one but two, and I’m not sure what that says about me.
Almost all of the USB to PS/2 mouse adapters are purely rewiring, but one isn’t : HIDMan (on Github). That will accept USB keyboards and mice (up to five buttons) and output PS/2 (or serial mouse). It can be fairly easily made at popular PCB fabrication places as it’s open source. I’ve recently had a few made and they’re excellent, enabling me to use a modern remappable USB keyboard[1], and will help if I want move on from my Logitech MX518, probably the last multi button mouse to support both PS/2 and USB directly.
To go the other way, there are many PS/2 to USB adapters on the market, but they’re of varying quality, don’t tend to stay in manufacturer catalogues, and typically contain one of only a few basic chips/USB IDs, but you can’t see what chip is in them so the best advice is normally ‘buy Startech’. The reliable way is likely to be to buy a TMK keyboard protocol converter (also supports mice), again the firmware and hardware are open source.
One good reason to buy a TMK (I’m going to, just haven’t yet) is for mice with more than three buttons. Whilst USB does support multi buttons natively, all the PS/2 to USB converters I’ve tried so far don’t, I had to use real PS/2 to see five buttons enabled. TMK claims they support five button mice so I’ll be buying one to handle the slightly ridiculous signal path of USB keyboard/mouse->HIDMan->fancy PS/2 KVM[2]->TMK converter->USB (yes, the PS/2 KVM does also plug directly into PS/2 only systems, one system using a serial mouse and AT keyboard, and a Sparcstation using a cheap F1DE083UK[3] PS/2->Sun converter).
If you don’t want to do TMK, note my experiences with seeing what adapters a MiSTer FPGA system supported PS/2->USB mice was (may have changed now):
Works :
0557:2221 (unmarked adapter). Identifies as : Aten Winbond Hermon
0557:2221 Branded Aten UC-10KVM. Same chipset as unmarked adapter!
04b4:2324 (unmarked adapter) Cypress Semiconductor USB PS/2 bridge
Non working :
0d3d:0001 Tangtop Ltd HID keyboard adapter (the square one. Not a surprise, it is only designed to support keyboards)
13ba:0018 PCPlay Barcode PCP-BCG4209
13ba:0018 another unmarked adapter.
Do you feel lucky?
[1] My Unicomp hardwired Dvorak buckling spring keyboards died. The choice is then repair them (will take a while, fiddly), ship a new one from the US (slow, expensive), or buy a HIDMan and a programmable keyboard off the shelf - current solution. The HIDMan is great, the Montech TKL I bought less so - if you keep replugging it it sometimes forgets what keys do, or its lighting settings.
[2] A decent second PS/2 KVM can be very substantially cheaper than a USB one, is more appropriate if you need to control a lot of old systems, and you may already have gathered the expensive cables from other KVMs. Let's just say this home study has substantially more than one computer (or even ten) and is pretty much a 90s systems museum..
[3] Search for 'Belkin Omniview universal USB to ps/2 adapter for Sun' on ebay UK. It's there, is a tenner, and works. Had difficulty getting VGA->13W3 working so used a separate passive adapter for that.
One of things that I really appreciated about the pre-iMac Macintoshes was ADB (Apple Desktop Bus).
One could daisy-chain devices. It was practical and especially useful when the Mac was not nearby.
There was no crawling under desks, wondering which port on the back of the computer was the right one.
One ADB port became many ADB ports: mouse, keyboard, joystick, graphics tablet and so on although I never had more than 3 devices connected.
And because there was a 5V charge running along the bus, the Mac could even be started by pressing the button on the upper right on the keyboard.
It was a well-designed feature that I appreciated.
FYI you can now buy the Wombat ADB to USB converter (works in both directions) for quite a reasonable price, which includes the 5V switch on functionality even if a USB keyboard is used! Supports mice and keyboards.
There are various cheaper hobbyist projects, but as usual they don't handle all the edge cases, and once the creator has scratched their itch they don't keep up maintenance.
The Wombat is $39. I realise not everyone has money, and some people have time to waste or things to learn, but seriously fiddling around with Arduinos vs paying $39 for something that Just Works
Yeah I had my PS2 mouse and keyboard swapped for quite a while on one of my desktops. Linux didn't care, it saw them as 2 ports. found the keyboard on a port and mouse on a port. I only realized I had them swapped when I tried to go into the BIOS setup for something and wondered why the keyboard was unresponsive... (I'd already disabled the notice to halt on no keyboard or it probably indeed would have stopped with the infamous 'No keyboard detected press F1 to continue'.)
That's a bit of an anachronism, and not something written by Raymond Chen.
For those kids too young to remember, about 20 years ago Wikipedia discovered that the common DB9 plug/socket, used on PC's, manufactured by 100's of different manufacturers, available at 1000's of outlets and in their nascent online catalogs, used the Canon DE9 design. And Wikipedia set out on it's mission to correct the world. With considerable success, as can be measured today by searching the internet for DE9 and DB9 manufacture and supply.
Indeed, most doublespeak is the product of clear thinking and is language carefully designed and constructed to appear to communicate when in fact it doesn't. www.good-words.fans
It is a DE-9 connector, the D is the shape, the E is the "sub-miniature" size (added after the standard was created I believe) and the 9 is the pin count.
DB-25 is the B size socket with 25 pins.
Canon (the purveyor of printers) has nothing to do with this, the company which invented the connector standard was Cannon (note 2 Ns) which is now ITT Interconnect Solutions.
Not sure if you read the actual article by Raymond or not, but he doesn't mention serial anywhere, so I don't know how you're saying the article wasn't written by him.
All of the D-type connectors were called "sub-miniature", because they were just that when compared to most comms/computer connectors during the era when they were introduced.
So more formerly, a DB-25 is a D type sub-miniature, B-sized, with 25 pins.
What is erroneously called a DB-9 is actually a D type sub-miniature, E sized, with 9 pins ... so it's actually a DE-9 (as pointed out above).
With that said, I've actually used D-sub, B-sized connectors with only 9 pins, in a single line down the center ... a true DB-9. They were in some old test equipment that we were re-purposing. I have absolutely no idea why they built it with such a non-standard part ... In about 1990 I called Amphenol for spares. They told me that they made them for a limited time in the early 1970s for a government contract, and they sent me a box full of old stock, gratis (individually wrapped, complete with pins, hoods & hardware). I probably still have a couple dozen or so of each (male and female) in my junk collection. I've never seen 'em anywhere else.
A pedant of the genre might point out that the D-sub connectors are all supposed to have parallel rows of pins (the DD-50 has three rows, the rest of the series have 2 rows) but what else would you call the things?
> the connector standard was Cannon (note 2 Ns) which is now ITT
I knew it wasn't the camera/printer company. Audio technicians of my generation called certain microphone connectors "Cannon plugs", because in 1923 Cannon introduced a meat-grounder, which by 1927 had morphed into the standard film-studio sound connector. SwitchCraft's "XLR" was a bit sleeker/cheaper and ate Cannon's lunch, but by then Cannon was making 100+ pin Mil-spec stuff and maybe didn't want the cheap business.
https://www.ittcannon.com/about/1920s-cannon-p-connectors <note URL
https://web.archive.org/web/20120309015738/http://www.ittcannon.com/uploadedFiles/Product_PDFs/History.pdf
Cannon also invented the D-Sub series.
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