Wombat ADB-USB Input Converter

Bridge keyboards and mice with classic hardware!

The Wombat is a bidirectional ADB-to-USB and USB-to-ADB converter for keyboards and mice.

Connect modern USB keyboards and mice to a classic ADB-based Macintosh, Apple IIgs, or NeXT
Connect legacy ADB input hardware to a USB-based computer running Windows, OSX, or Linux

No special software or drivers are needed – just plug it in and go.

Now you can finally use a modern optical mouse with your vintage Macintosh, or amuse your coworkers with a retro ADB keyboard on your work machine. ADB-USB Wombat is an indispensable tool for Apple collectors and enthusiasts.

Optional accessories for your Wombat:

ADB-USB Wombat is great for breathing new life into your vintage Apple hardware collection. If you love old Macs, you know ADB keyboards are expensive and hard to find, and ADB mice are sticky and trouble-prone. With the Wombat, you can substitute modern USB input peripherals instead. Or if you swear by your old Apple Extended Keyboard, you can use it with your modern computer. Visitors are sure to smile when they see you running 1980s Apple input peripherals on your current-year machine.

No external power source needed
On-board power key for remote turn-on
Upgradable firmware
Works with your favorite mice and keyboards

The Wombat was developed by Steve Chamberlin, here at Big Mess o’ Wires. See the blog archive for technical details on its software and hardware.

Compatibility

The Wombat hardware is compatible with all Apple computers, keyboards, and mice with an ADB connector (a 4-pin mini DIN), including most early Macintosh computers and the Apple IIgs, as well as some NeXT computer models. It is also compatible with standard USB keyboards and mice with a USB-A connector. When in ADB-to-USB conversion mode, it works under Windows, OSX, Linux, Chrome OS, or any other operating system that supports USB HID input peripherals.

Security dongles, joysticks, and other less common devices are not supported. The Macintosh Plus, Mac 512K, and Mac 128K computers use an older non-ADB connector for keyboards and mice, and are not supported.

USB to ADB

Connect USB keyboards and mice to a classic ADB-based Macintosh, Apple IIgs, or NeXT computer. Requires an ADB cable (not included). Set the Wombat board’s jumper to USB input mode, as shown on the diagram. Power will be supplied from the computer. Use an ADB cable to connect the board’s ADB port to the computer’s ADB port.

A single USB peripheral can be connected directly to the Wombat board’s USB-A port at CON1, or a standard USB hub can be used to connect multiple peripherals at once. When in this mode, the Wombat supports one USB keyboard and one USB mouse, as well as any number of ADB keyboards and mice, all used simultaneously.

Standard bus-powered USB hubs are recommended. Some externally powered USB hubs (with their own independent power supply) can backfeed power into the Wombat even when it’s off, causing problems.

Right Click Behavior – Most ADB mice had only one button, so the USB mouse’s right button is handled one of two ways. Macintosh mode sends a control + click event to the host, which opens context menus in Mac OS 8 and later. NeXT mode sends a true right click event to the host. The default is Macintosh control + click mode. Toggle between the two modes by clicking the USB mouse wheel button (button 3).

Mouse Wheel Behavior – ADB mice did not have a mouse wheel. USB mouse wheel movements will send up/down arrow key events to the host. This works well for document scrolling and file dialogs. If necessary, this “mouse wheel arrow keys” behavior can be disabled using the custom key mapping tool, described below.

Beginning in firmware 0.3.9, a long press of the mouse wheel button (more than half a second) will change the Wombat’s built-in mouse movement hardware scaling. Each long press increases the scaling by a factor of 2. This is helpful when using certain USB mice whose tracking speed is too slow or too fast even after making adjustments in the host OS’s mouse control panel.

ADB Power Key

Power Key – Original ADB keyboards had a power key – a square or rectangular key with a triangle logo that could be used to turn on some later models of ADB Macintosh computers. There’s an equivalent button on the Wombat board that will function as a substitute power key, even when the computer is off.

Connections for Standby Power

Standby Power – If the Wombat is powered from an auxiliary source (optional), it can continue working even when the computer is off. In this case, the PRINT SCREEN key or F13 key on a USB keyboard will also function as the power key to turn on the computer. To use this configuration, set the board’s jumper to USB+PWR mode, as shown on the diagram (board version 1.1 or later only), and connect a standard USB charger to the board’s USB-B port at CON2. For correct operation, an auxiliary power source must always be present when the jumper is set to USB+PWR mode.

ADB to USB

Connect ADB keyboards and mice to a modern USB-based computer. Requires a USB-Mini-B cable (not included). Set the Wombat board’s jumper to ADB input mode, as shown on the diagram. Power will be supplied from the computer. Use a USB-A to USB-Mini-B cable to connect the board’s USB-B port at CON2 to the computer’s USB port. This is the same cable commonly used to connect mobile phones and other devices to a computer. In this mode, nothing should be connected to the Wombat board’s USB-A port at CON1.

A single ADB peripheral can be connected directly to the Wombat board’s ADB port, or multiple peripherals can be daisy-chained, using the ADB pass-through connector found on all Apple ADB keyboards. When in this mode, the Wombat supports one ADB keyboard and one ADB mouse, as well as any number of USB keyboards and mice, all used simultaneously.

The ADB peripherals will appear as standard HID input devices to modern Windows, OSX, and Linux computers. No special drivers or other software are needed.

Firmware Updates

The Wombat firmware can be updated to fix bugs and add new features. Download the firmware.hex file from the downloads section below, and copy the file to the top-level directory a USB flash drive. The USB drive should be formatted with the FAT32 filesystem. Most USB drives already come preformatted this way.

During the firmware update process, the Wombat board can be powered from an ADB-based computer and ADB cable attached at CON3, or from a standard USB charger and USB-B cable attached at CON2. If powering from an ADB cable, set the board’s jumper to select USB input mode. If powering from a USB-B cable, set the board’s jumper to Standby Power mode (USB+PWR).

Disconnect all power from the Wombat board. Plug the flash drive directly into the board’s USB-A port CON1 – do not use a hub. Hold the board’s power key button while you connect the power source to turn on the board. Continue to hold the button for a few seconds, until the A and B status LEDs begin blinking rapidly. The update process takes about 10 seconds. When finished, the LEDs will blink slowly together, once per second.

During a firmware update, both LEDs are used to indicate update status:

slow alternating blinks of A, then B (1 blink/sec) – bootloader is searching for a firmware file
fast alternating blinks of A, then B (8 blinks/sec) – bootloader is updating the firmware
slow synchronized blinks of A and B together (1 blink/sec) – bootloader finished successfully

If B blinks several times while A remains off, it indicates a bootloader error:

2 blinks – no valid firmware exists on chip, can’t start main Wombat program
3 blinks – no firmware files found on USB drive
4 blinks – error in firmware file (checksum mismatch or illegal data)
5 blinks – error while updating firmware in chip memory

LED Status Codes

The A and B LEDs on the Wombat board display status and error information. (The A LED is labeled RUN on some boards). During normal use, the A LED will turn on when the Wombat has a working data connection (ADB or USB) to the host computer. The B LED will blink whenever there’s keyboard or mouse activity.

Help Commands

You can interact directly with the Wombat by typing help commands on an attached ADB or USB keyboard. Open an empty text document or command prompt on your computer. The Wombat will “type” its responses to your commands, so they appear on the screen.

Control-Shift-Capslock-T – Cycles between key mapping types US-GENERIC (ANSI QWERTY), ISO-GENERIC (UK and other non-US QWERTY), ISO-FR (AZERTY), and ISO-DE (QWERTZ)

Control-Shift-Capslock-G – Shows the currently active key mapping type

Control-Shift-Capslock-V – Displays the firmware version number

Control-Shift-Capslock-I – Displays the USB vendor and product ID or ADB handler ID of the keyboard and mouse

Control-Shift-Capslock-C – Enters keydump mode. While in this mode, the USB key code is displayed for each key that you press, along with the corresponding ADB key code it’s mapped to (or vice-versa). This can be helpful for troubleshooting key mapping problems.

Control-D – Exits keydump mode.

International Keyboards

Non-US international keyboards are supported by the Wombat. These include country-specific keyboard layouts like British, Canadian French, Danish, Greek, AZERTY variants, QWERTZ, and others. You’ll need to select the appropriate keyboard type in your operating system’s keyboard control panel, in order for the key mappings to work correctly.

System 7 Keyboard Control Panel

Two specific keys on ISO keyboards may require extra attention. If the key above TAB incorrectly behaves like the key to the right of LEFT SHIFT, you can switch ISO mode on/off to correct it. See details in the Help Commands section.

ISO Keyboard Key Swap

USB-to-ADB – Best results are obtained with Apple-brand country-specific USB keyboards, or any brand US-layout USB keyboards. In many countries, the country-specific PC-type USB keyboards have a different symbol layout than Apple ADB keyboards. These PC-type USB keyboards may be used, but key mappings for some symbols will be incorrect where differences exist between the Apple and PC-type layouts.

ADB-to-USB with Mac OSX – The first time you connect the Wombat to a modern Mac, a wizard will appear and attempt to detect the keyboard type. For non-US keyboards, you should select an ISO keyboard type from the wizard. If the key above TAB incorrectly behaves like the key to the right of LEFT SHIFT, even when the Wombat is in ISO mode, you may need to delete the OSX keyboard preferences to force the wizard to run again. Set the Wombat to ISO mode, delete the file /Library/Preferences/com.apple.keyboardtype.plist, restart the computer, and follow the wizard steps when it reappears.

Windows 7 Text Services and Input Languages Control Panel

ADB-to-USB with Microsoft Windows – Under Windows, when using country-specific ADB keyboards, you’ll need to select an Apple keyboard sub-type when choosing the keyboard type in the Windows preferences. The keyboard type is selected in the Text Services and Input Languages control panel. E.g. select a keyboard type of United Kingdom (Apple), French (Apple), or German (Apple) rather than the default United Kingdom, French, or German. If you don’t see the Apple sub-types listed, you’ll need to install the Apple keyboard driver applekeyboardinstaller64.exe.

Custom Key Mappings

With firmware version 0.3.0 or later, you can create your own customized key mapping tables. Change which keys behave as Command and Option, reassign the function keys to new purposes, or design other custom mappings. See the Wombat Keymap Tool for details.

What are ADB and USB?

ADB connector

From 1986 through 1998, ADB (Apple Desktop Bus) was the standard system for connecting peripherals like keyboards and mice to Apple computers. It was used by the Apple IIgs, as well as all early Macintosh models except the Mac Plus, 512K, and 128K. The ADB connector is a round mini DIN 4-pin, and is physically identical to the S-Video connector.

USB-A connector

USB (Universal Serial Bus) is the dominant standard today for connecting keyboards, mice, and other peripherals to a computer. Nearly everyone will recognize the familiar rectangular USB-A connector that’s used to plug a device into a host machine. USB replaced a variety of earlier standards like Firewire, ADB, and PS/2. Every Apple computer since 1998 has used USB for its input peripherals.

Converting between the two systems involves more than just a physical plug adapter. ADB and USB high-level protocols are fundamentally very different, and also have different signal speeds, signal formats, and voltages. ADB and USB input peripherals have different communication behaviors too. ADB keyboards and mice use event-based reporting, and only communicate when something has changed, whereas USB keyboards and mice communicate their full current state whenever asked.

Documentation

Instruction manual: Wombat instruction manual

Downloads

ADB-USB Wombat latest firmware version: adb-usb-wombat-0.3.11 (September 28 2026)

Older firmware versions: (try these if the latest version gives you problems)
adb-usb-wombat-0.3.9 (August 9 2023)
adb-usb-wombat-0.3.8 (October 21 2022)
adb-usb-wombat-0.3.7 (September 11 2021)
adb-usb-wombat-0.3.6 (June 25 2021)
adb-usb-wombat-0.3.5 (April 8 2021)
adb-usb-wombat-0.3.4 (April 8 2020)
adb-usb-wombat-0.3.3 (September 19 2019)
adb-usb-wombat-0.3.2 (September 9 2019)

3D-printable enclosure (contributed by James Kelly, Creative Commons license with attribution)

Get One Now

Check out ADB-USB Wombat at the BMOW Store.

301 comments

301 Comments so far

Brielle Harrison - June 23rd, 2023 8:43 pm

I have owned a few of the Wombat devices. I really enjoy them. Sadly many of the new mice out there present themselves either as a keyboard or as a combination of both keyboard and mice (likely to handle the multiple buttons they provide). How can I get the wombat to use these mice?

Additionally, 2.4Ghz wireless USB does not seem to be supported either (Microsoft Sculpt Keyboard) or mice with a USB dongle that connects to the mouse wirelessly. Is there something I can do to help enable these devices?

Is the firmware open sourced?
Brielle Harrison - June 23rd, 2023 8:48 pm

Chris Peak, if your mac is like my Mac mini (late 2014) then you’ll find that early boot option key combinations only work with the USB port nearest the power supply (in my case). This was a semi-obscure piece of knowledge. I was pulling my hair out trying to figure it out. Maybe the option key or other issues is due to the keyboard (and wombat) being connected to the “wrong” USB port.
Chris Peak - June 24th, 2023 11:02 am

Brielle, no .. my machine is an old 1997 Beige G3 PowerMac. No built-in USB back then, just ADB. The Wombat sits between a USB keyboard/mouse and the venerable ADB bus.
MarkW - June 30th, 2023 10:05 am

Hi Steve, I see that there is room for another connector “CON4” on the PCB but I didn’t see it mentioned in the instructions or here in the comments. Can you explain what it is for?. Can I solder on a 4-pin mini DIN and gain another ADB connection? I would like to connect a USB keyboard and a regular ADB mouse to my IIGS.
Steve - June 30th, 2023 3:37 pm

The empty ADB footprint is wired in parallel with the other ADB port. You could add an extra ADB mouse or keyboard there if you wish.
Josh Lucas - July 3rd, 2023 10:44 am

I love my Wombat so much. Great work.
I’d suggest a correction to the firmware update section of the help document here, though. I was updating firmware today and my wombat would not see the firmware file unless i formatted the USB drive as MBR rather than GUID. As GUID is the default for mac Disk Utility, people will likely have to select this manually when making a firmware update USB.
Keep up the great work!
Jake - July 4th, 2023 3:07 am

I’ve recently started using the Wombat a bit more regularly, and I’ve noticed a peculiar thing when using it in ADB to USB mode on Windows. The computer never goes to sleep while the Wombat is plugged in. This happens on both a work laptop running Win10 and my home PC running Win11. It is the only USB device when plugged into the work laptop.

The OS can be placed into sleep manually no problem, it only affects the automatic sleep after inactivity setting. I can’t see any other issues in behaviour. I’m on the latest firmware and the device is working great. LEDs ON and A are always lit and LED B only flashes when keys are pressed.

Is this a known behaviour?
Geoff - July 9th, 2023 1:09 am

Hi all, just came across this page. The Wombat looks like such a great idea! Does anyone know if the Wombat would allow an ADB graphics tablet to work on a USB era Mac, pls? I have 2 Wacom 12″ tablets and would like to hook them up to G4 era computers.
I expect it may not support all of the functionality.
TIA.
Steve - July 9th, 2023 2:08 pm

Sorry, tablets and other peripherals besides keyboards and mice can’t be translated by the Wombat firmware.
Brielle Harrison - July 9th, 2023 2:11 pm

I wanted to bump my previous comment that didn’t seem to rate a response. Most newer mice seem to register themselves as both keyboards and mice due to additional buttons and functionality. Is there a way to modify the firmware to detect these types of mice and at the very least just enable them as mice and ignore their keyboard functionality?

I’d be happy to contribute if the firmware is open source. Let me know.
Steve - July 9th, 2023 3:57 pm

The Wombat firmware is not open source, but you may want to check out the open-source TMK adapter if you’re looking for something you can tinker with. See the comments above for some of the wireless mice and keyboards that other people have used successfully. I personally have the Logitech KM117. The firmware uses the first connected USB keyboard and mouse that it finds, so if your mouse also id’s itself as a keyboard, you could try starting with only a USB keyboard and then connecting your mouse after the keyboard is recognized. Swapping the mouse and keyboard to different ports on your USB hub might also change the device enumeration order in a way that helps your use case.
v - September 16th, 2023 5:58 pm

Please consider an alternative to USB mini B for the secondary USB port on the Wombat. It’s by far the hardest connector type to find in brick-an-mortar stores.
Tim - October 2nd, 2023 6:27 pm

Would you ever made a smaller version of this? I never bought this because how big it is and always waited to make a much smaller version for my projects. I could see you shrinking this and using switches for the jumpers instead to make it much smaller. I will buy a couple once you do.
Josef - January 17th, 2024 12:25 am

Any timeline on when more wombat cases will be available for purchase?
Steve - January 17th, 2024 8:53 am

The Wombat case is in stock now.
tony - January 26th, 2024 8:25 pm

love my wombat! thank you for creating it.

trying to use it on OS9, but no dice thus far. any tips?

the particulars are a 9.2.2 on a Mini G4 (yes, there’s a bit of voodoo involved, but this Mini is happy to work with all my other USB input devices).
Stephan - June 14th, 2024 1:28 am

Hello, i wanted to ask when the Wombat Board get back in Stock? Kind regards
Steve - June 14th, 2024 6:26 am

More Wombats are expected to be available next week.
Steve - June 21st, 2024 7:28 pm

The Wombat is back in stock now (June 21) in the BMOW Store.
Tim - June 21st, 2024 7:36 pm

WTH is with the emails im getting everytime someone comments here, the link to edit the settings dont work either
Stephan - July 16th, 2024 12:58 pm

I receive the Wombat and it works fine with my Apple Design Keyboard. But isn’t it about time for an upgrade from mini USB to USB-C? Luckily I still had a cable for it.
Anonymous - August 9th, 2024 6:30 pm

will this work for a apple keyboard to PC?
Anonymous - August 9th, 2024 6:31 pm

I Meant Keyboard 2
Jim Henry - August 28th, 2024 1:36 pm

I already have a couple of your ADB>USB active converters and am extremely pleased! Now, do you have passive adaptor for female ADB > USB C (m or F)? Is there any such thing as an ADB gender changer?
Steve - August 29th, 2024 11:53 am

I don’t think you will find a *passive* adapter for USB-to-ADB anywhere because those two standards are completely different. But you could add a passive USB-A/B to USB-C adapter to the Wombat, if needed for your computer.
Andrew - September 16th, 2024 7:22 pm

I’ve noticed that my Wombat when connected to a Windows device fails to activate the screen saver after x period of time. Its acting like there’s always activity on the Keyboard (AEKII) even when idle. Is tis a Windows issue or a issue with the Wombat?
Jake - September 16th, 2024 8:42 pm

I reported the same bug a while ago, across multiple PCs. It’s a Wombat issue for sure. Occurs even if no ADB device is plugged in.

It’s almost a feature, it acts like an undetectable mouse jiggler for work procrastinators 😛
Shawn Quick - November 9th, 2024 10:40 am

Hi Steve, received my wombat early this week. No joy however. Apple iigs. Standard ADB keyboard works just fine on the machine. I have yet to get the wombat with an any of my keyboards (tried both wireless and wired..and not gaming keyboards, just standard logi and/or MS). After the first initial attempts, I decided to upgrade firmware to the latest from this site. Then, not having luck, tried several other versions. F/W upgrade seems to go normally. fast toggling leds, 10 seconds, slow toggling A/B leds.
ADB port on computer works, as ADB keyboard works. When the wombat powers on, I get the slow A->B->A (1/sec) toggle on the wombat leds. It looks to me like ADB comm is not working. Only thing I can think of is I bought an S-Video cable from amazon (6ft) and that is not allowing the thing to work…although I don’t see any reason why it would not. What does the power on A->B->A->B blink mean? I am not holding down the ‘power’ button when booting. Anything I can do to debug? serial port console or anything? Thanks.
Steve - November 9th, 2024 12:41 pm

For 1-on-1 troubleshooting help with your personal equipment, please use the Contact link at upper-right of the page and we will do our best to help. It’s likely that the cable is the cause of the problem.
Frank - February 5th, 2025 10:31 am

Hi,

I just received the unit and it seems like it works well.

I have Apple ADB keyboard and mouse connected to a PC. This setup works fine when I have ADB connected with the mini USB Connect side by side. However, I have a use case where I need to use the full size USB port on the other side. Otheriwse, I cannot use this how I intended it. How do I reroute the “ADB to side by side mini USB port” to “ADB to Opposite side of USB port”?

Thanks
Steve - February 5th, 2025 11:35 am

How are you planning to use the Wombat? If you want to connect an ADB keyboard to a modern PC, then the large USB connector (USB-A) is not needed. That USB-A connector is only used when performing the opposite conversion: connecting a USB keyboard to an old Apple computer like a Macintosh SE or similar. If you have other questions that are specific to your installation, you can contact BMOW directly using the “Customer Support” link at the top-right of this page.
ben - April 6th, 2025 8:55 am

> trying to use it on OS9, but no dice thus far. any tips?
>
> the particulars are a 9.2.2 on a Mini G4 (yes, there’s a bit of voodoo involved, but this Mini is happy to work with all my other USB input devices).

Really late reply, but I can confirm at my Mac Mini G4 @ 9.2.2 works with the wombat when used with a USB A to mini B cable — but it’s important to use a cable with power AND data lines.
Tim - July 3rd, 2025 1:28 pm

Hi, love this project. Is there a new eta on when more stock might be available?
Steve - July 4th, 2025 11:02 am

The next batch is in production right now, but taking a bit longer than expected. I hope to have them ready in about a week or so.
voelker - July 11th, 2025 11:14 pm

hi, can i order now even though it says sold out on the website? i can still add to cart via this page

then i just wait for production to complete
Steve - July 12th, 2025 4:52 pm

Sorry, we’re not accepting more orders until we have the product in hand, just to be conservative in case there are any unexpected problems with manufacturing or crazy surprises with tariffs.
Ford - July 22nd, 2025 9:32 pm

Glad to see this is back in stock! The timing is hilarious because had given up on waiting and *just* spent the weekend bit banging ADB on an old Arduino and Raspberry Pi. Got it working great with both keyboard and mouse. It was a lot of fun, but your solution is obviously a lot more elegant and doesn’t require individual jump wires plugged directly into my SE’s ADP port!
Kirk - August 2nd, 2025 1:47 pm

I just received my Wombat and case. I have the Original AppleDesign Keyboard from when I added it on my Mac SE back in 1995. (Got it from a Quadra I think…) It’s ADB of course, and I plugged it in via the Mini-USB with a USB-C adaptor, and it’s connected to my Mac Mini M4. That’s what I am typing on now!! The CAPS lock light works too!

Man… the nostalgia. I need to find my original SE keyboard and try that too. SO DANG COOL!

I kept watching the website every day for a month and then got one. I am so happy!

Thanks you BMOW!!
Chuck - August 4th, 2025 5:01 am

I have a Wombat with a cheap USB Hub and a wireless keyboard and wireless mouse connected. The keyboard works great, and the mouse works great separately, but I can’t get them to work together. The keyboard always works. I have tried plugging them into different ports on the hub. Also confirmed they both work together on my Windows machine plugged in directly or into the cheap USB Hub.

Should I look at adding power from the USB-micro port on the Wombat? I am thinking maybe the power draw is too much for bus power from the ADB?
Steve - August 4th, 2025 8:29 am

An auxiliary power supply at CON2 is certainly worth trying – don’t forget to move the jumper to the USB+PWR position. Or it might a keyboard that has an integrated pointing device that gets detected instead of the mouse. If you continue to have trouble, please use the Customer Support link at upper-right of the page to get in touch directly.
Ed H - September 1st, 2025 6:23 am

Hi Steve,
I just got my Wombat, and love it. So here’s my issue I can’t seem to find an answer for. It has to do with the right-click context menu. I recently got a Macintosh SE FDHD, with the original extended keyboard and mouse.Basically, I decided to rip out all the guts of the SE due to hardware issues I didn’t want to deal with, but wanted to do something with the case, keyboard (ADB connectors) and mouse. I got a Mini PC and 8″ monitor, hooked up the Wombat so I could utilize the keyboard with the USB of the Mini PC. It works great, but since it’s a one button mouse, I can’t do a right click to bring up a context menu. Is there any way to do this? I know it would be easy with a modern keyboard and mouse, but I’m trying to maintain the “cool” factor of the package. Also, I know there are keyboard shortcuts using the F10 key, but there are no “F” keys on this one. Any thoughts to get the right-click context menu working with this setup? Thanks
Steve - September 1st, 2025 9:12 am

I think this may be more of a Windows question than a Wombat question. Google says you can use PowerToys to map a key to open the right-click context menu in Windows 10/11. Shift+F10 is another option as you mentioned. If your keyboard doesn’t have an F10 key, you could swap it for an Apple Extended Keyboard or use the key mapping feature to assign another unneeded key to behave as F10. https://www.reddit.com/r/Windows10/comments/10k28fk/right_click_shortcut/
Ed H - September 1st, 2025 10:14 am

Thanks for the super-fast response. I will check out your suggestions.
Ed
Scott - September 14th, 2025 3:40 pm

I got the wombat so I could use a modern keyboard and mouse with my old Apple IIgs.

I have tried two different keyboards, and neither one works at all. I have tried both USB and USB+PWR modes. Of course I added external power when using the USB+PWR mode. It didn’t make any difference.

I think maybe part of the problem is that both USB keyboards I tried are too fancy. They both have LED lighting. One of them is a Keychron that can switch from wired to wireless, and when it is wired it attempts to charge its internal battery.

Is the solution to go out and get a boring old USB 2.0 keyboard, or is there some other troubleshooting step I can try first?

The wombat works great with my USB mouse. It also works great for using an ADB keyboard with my modern computer. So I don’t think the wombat itself is broken. I also confirmed the firmware is the latest version.
Steve - September 15th, 2025 9:01 am

Yes, it would be worth trying a more plain vanilla keyboard since combo devices with integrated pointing devices or game functions may not be identified correctly by the Wombat. I’d also suggest trying a keyboard by itself, without the mouse, since some gamer mice with macro capability may ID as both a mouse and a keyboard. Please use the “customer support” link to get in touch directly if you need further individual help.
Chris - September 15th, 2025 1:29 pm

That shouldn’t be a problem, I’ve used Keychron boards (K2, K8, C1, Q60 Max) with the Wombat and a IIgs, all worked fine. The LED stuff is (AFAIK) invisible to the Wombat. I use it now with Tokyo60 boards that have backlighting as well, works great.
Scott - September 15th, 2025 2:14 pm

@Steve @Chris thanks. I have a Keychron K10 Pro an also a Corsair STRAFE. Neither are working with the Wombat. I am trying to change various things. USB/USB+PWR mode. Different USB cables. It doesn’t seem to matter. The B LED on the wombat does not blink when I press keys on the keyboard. Every other mode works, including the USB mouse. I have re-read the instructions, and do not believe I am doing anything incorrectly. Any ideas?
Scott - September 15th, 2025 3:36 pm

I borrowed a Logitech K120 from a friend. The most boring standard keyboard imaginable. It works.
Richard - September 24th, 2025 11:58 am

Hi, I scanned through the comments but I’m not sure my exact use case was discussed.

I have multiple 68k Macs that I would like to use a single ADB keyboard and Mouse with. Unfortunately ADB keyboard mouse switches seem to be very difficult to source.

My crazy idea is to use a USB KVM along with BMOW Wombat adapters (ADB ↔ USB) on each Mac. In theory, that should let me use one ADB keyboard and mouse across multiple vintage Macs by converting them through the Wombat into USB, switching with the KVM (while machines are powered off), and then back to ADB where needed.

Would this work?
Steve - September 24th, 2025 2:15 pm

Check out this person’s setup, it sounds like what you need: https://68kmla.org/bb/index.php?threads/keyboard-setup-with-bmow-wombat.46031/
Xanxi - December 7th, 2025 4:10 am

Hi there.
I have bought recently a wombat and printed a nice case thanks to the stl file.
Works great with my Apple IIGS with my Logi Ergo M575 trackball, but i can’t have a Microsoft wired keyboard 600, not a similar wireless Microsoft keyboard to work. I guess those one are pretty standard and used in vast numbers. Only an unknow brand with illuminated keys is working. Is there a way to have those Microsoft keyboards to work or a whitelist of working keyboards?
About the illuminated one, i guess it is not a good idead to drain current from the AppleIIGS ADB port for lights?
Regards.
Alex - January 13th, 2026 11:49 am

Hello, I wanted to get another Wombat. Any idea on a restock date?
Todd - February 14th, 2026 8:46 am

Is there any known incompatibility with the Mac Portable (5120, 5126)? I have tried two separate Wobats, with latest firmware updates and even used the powered USB option. The Portable works find with ADB mouse and keyboards but the Wombat will not let me use an Apple USB keyboards and mouse.
Steve - February 15th, 2026 6:30 pm

Thanks for the report, there does seem to be a compatibility issue with the Mac Portable – I’m surprised this hasn’t come up before, but I confirmed it with the help of a friend’s Portable. With the Wombat powered by the Portable, the Portable’s unique startup circuitry forces the Wombat into bootloader mode when the computer is turned on (alternating blinking of LEDs A and B ). This prevents normal keyboard/mouse function. The solution is to move the input jumper to the USB+PWR position and attach a USB power supply to CON2. With the Portable still off, confirm that the Wombat’s ON light is illuminated due to the external power supply. Then turn on the Portable and the Wombat should work normally. Please use the customer support link to get in touch directly if you have any further trouble.
Dani S - April 28th, 2026 6:06 am

I also have a keychron V6 MAX keyboard which is tri-mode (wired/2.4g/bluetooth). When I connect the keyboard through the wombat via a cable (through my USB hub) or using the 2.4ghz dongle, the keyboard connected, however none of the keys worked, including the caps lock key. I tried restarting a few times and verified that the Wombat registers an ADB keyboard via Tattle Tech. This is on a Macintosh II with 7.1.2 installed.

I’m a little disappointed this isn’t working. I do have a USB sniffer I could use if that can help you at all, but there definitely seems like an incompatibility with super modern keyboards. When I plugged in my Macintosh G4 Keyboard (A1048) it worked fine, even without needing to restart the computer.

My Keychron M3 8K mouse works fine, I even have it routing through my G4 keyboard. I do want to discontinue using the older keyboard since I have newer ones available. Please let me know if we can sync to do some usb debugging together!
Dani S - April 29th, 2026 1:53 pm

I was doing a little more troubleshooting. Seems like when I set the adb wombat to USB+pwr mode with a walmart Onn branded usb2 hub, I was able to get my keyboard to work, however the mouse wasn’t working. I am wondering if there is some kind of power thing going on with the wombat and some modern devices.
Steve - April 29th, 2026 4:14 pm

Hi, you can use the Customer Support link at upper right if you need to get in touch about individual hardware issues, returns, etc. Yes the USB stack on the Wombat’s microcontroller is simpler and more limited than what exists in a full-fledged OS, and also has a limit of one mouse and one keyboard. Some fancier USB devices are designed as compound devices, like a keyboard with an integrated pointer or a mouse with a macro key feature, or other tech issues that cause compatibility problems with the Wombat. For this reason I recommend using more “plain vanilla” USB devices as ADB replacements if possible.

Power in USB-to-ADB mode is supplied by the NeXT, Apple IIgs, or vintage Macintosh the Wombat is plugged into. Tools like TattleTech will always show that an ADB mouse and keyboard are present when the Wombat is plugged in, regardless of whether any USB devices are present or working, since it’s the Wombat that implements the ADB communication with the host.

If the Keychron is a must-have for you and you’re not able to get it working as you’d hoped, please reach out to Customer Support to arrange a product return. Thanks!
Brian - June 9th, 2026 6:51 am

The Wombat is worth every penny of its very reasonable price.

I got a working Macintosh LC520 left out next to an apartment building without a keyboard and mouse. I used the paperclip trick to boot it but couldn’t do anything with it without its ADB keyboard and mouse. Vintage Apple ADB keyboards and mice are very expensive now, fortunately, I discovered the USB-ADB Wombat that enabled me to use a wired keyboard and mouse through a powered USB hub to use the LC520. To boot the LC520, pressing F13 on an Apple keyboard is required, pressing F13 on a usb keyboard connected to the LC520 ADB connector through the Wombat doesn’t work, but that isn’t a problem because the Wombat has a pushbutton that, when pressed, boots the LC520.
Steve - June 9th, 2026 3:52 pm

Thanks for the review! If using a powered USB hub and with the input jumper on the USB+PWR position, you should see the same behavior from pressing F13, PrintScreen, or the side power button. All three activate the same transistor which pulls one of the ADB pins low, to signal a power button press.
BD - August 19th, 2026 10:01 am

While running Win11, has anyone else experienced “2026-08 .NET Framework Security Update (KB5120708)” making their ADB mouse go away? I am using a Kensington Turbo Mouse (The reason why I got two wombats was to use these great trackballs) and after installing KB5120708, the curser disappears. Uninstall KB5120708 and it reappears.
Steve - September 29th, 2026 2:37 pm

Wombat firmware 0.3.11 was just released to fix a serious bug in the handling of USB keyboards and mice. The bug prevented USB devices from being recognized by the Wombat if their HID report descriptor was larger than 255 bytes. In simple terms, fancy keyboards and mice with lots of buttons and other features often did not work, due to the larger size of the data they needed to report. https://www.bigmessowires.com/2026/09/29/adb-usb-wombat-firmware-fix-for-unrecognized-usb-keyboards-and-mice/
BD - September 29th, 2026 4:32 pm

Steve, you are a peach…at least as amazing as your products! All back to good. Please keep up the great work.
BD - September 29th, 2026 9:36 pm

I should add that I can’t verify whether the update helped or not. I disconnected the trackball once it stopped working (hard not to add updates these days with all of the zero days flying around). I plugged it in and it started working. That is hardly a proper testing design.
So, either the update solved my issue or this Wombat is so bulletproof it fixed itself *despite* the update. Steve, you restore a good chunk of my questionably misguided faith in humanity, lol!
BTW, I use a Wombat w my work PC and it confuses work’s Microsquishy Teams. Somehow the chip keeps Teams from sensing when I’m there or away so it is now 100% at my command, lol.

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