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Hi all,

 

I've been getting back into the Mac liberation game lately and I seem to be acquiring more machines than I have keyboards/mice and monitors for :):beige::quadra::pb::cc: . I've seen around the forums here that, if you can get your hands on one, the Dr. Bott ADB KVM is the best. I've also seen mention of the "cheapie" KVM's, which I imagine are just the old mechanical switch types. The problem is that I can't seem to find a source for either of these types of KVM's.

 

Does anyone know where to get these ADB switches, either the Bott version, or the switch only? 8-)

 

Thanks!

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Personally, I'm a huge fan of the old NTI KVMs. The pre-USB NTI KVMs support Sun, PS2, and ADB keyboard/mouse, including translation between each. There doesn't seem to be a whole lot of information about them online, so I put up what I figured out on my Old NTI KVMs page.

You can use either a Sun, PS2, or ADB keyboard & mouse, and the systems can be any combination of the above.

The KVMs are readily found on ebay, and sometimes go for fairly cheap. I've gotten a couple 8 port systems for ~$20 in the past, sometimes including shipping. I'm currently using a 2x16 matrix and a 4x32 matrix (meaning 2 or 4 keyboards/monitors can connect to any of up to 16 or 32 connected systems).

The KVMs support daisy chaining, so you can chain the KVMs together to get more ports if you want, and the KVMs are aware of each other so you can switch to any port on any of the chained KVMs from the same keyboard.

The only catch is cabling. The NTI KVMs natively use a Sun connector and you need appropriate cables to convert between that and PS2 and ADB connectors. This MKTINT-1 cable from kvm-switches-online works fine. It is advertised for plugging a keyboard into the KVM, but it works perfectly fine for systems, just keep in mind the ADB side is female and you'll need a male/male cable to plug it into systems. They used to sell varying lengths of the male/male Sun to ADB cabling, but that was discontinued not too long ago.

 

I've included some cabling pinout information, key mappings, and what the dip switches mean on my linked page.

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You can easily repurpose PS/2 or USB KVMs by replacing those connectors respectively with S-Video connectors. You can build an entire network of KVMs by replacing just the connectors on the KVM and terminal connections only, leaving any units in the middle of the setup stock.

 

Electronic switchboxen from TRENDNET are very inexpensive and come with all cables necessary. I'm standardizing on those and the OmniView series I've been using for 20 years.

 

There's another thread around here somewhere about KVMs.

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Personally, I'm a huge fan of the old NTI KVMs. The pre-USB NTI KVMs support Sun, PS2, and ADB keyboard/mouse, including translation between each. There doesn't seem to be a whole lot of information about them online, so I put up what I figured out on my Old NTI KVMs page.

 

Thanks for the tip, I will check these out!

 

Dr.Bot ones are nice / I also have a 12 port push button type ADB KVM made by Black Box

 

Thanks! Will check out this brand as well. Problem is, I'm very familiar with the equipment in the PC world, where you can search and find a plethora of information about "ps2 kvm's" or the like, but I had the hardest time finding anything for ADB (except for a 15 year old article about the Dr. Bott unit, and a bunch of e-stores who have the equipment listed but all OOS ;) )

 

You can easily repurpose PS/2 or USB KVMs by replacing those connectors /

Electronic switchboxen from TRENDNET are very inexpensive and come with all cables necessary.

 

I checked out your link; I like your re-purposing of PS/2 KVM's. At that point, I'd just need to buy the 4-pin mini DIN connectors for the consoles + the peripheral input, and pick up some extra DB15->HD15 for the console end. I might even have a PS/2 kvm kicking around somewhere Hmmm

 

Is there additional circuitry in these switches to trick the console into thinking that the peripherals are still connected? If so, are there any special considerations (e.g. using particular pins when wiring in the Mini DIN) that need to be observed when modifying such KVM's?

 

Thanks!

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That's what he's doing. But we're talking about re-purposing the KVM CABLES at the I/O switching network's extremities. No changes are made to the boxen/cable network connectors betwixt. These remain stock, whichever type or combination of types is chosen, PS/2 or USB. for a mixed platform switching system.

 

AFAIK, there has been no KBD or Mouse emulation on any of the KVM switches I've used. Maybe there is in the OmniView Mac Adapter, but that wouldn't have done anything for the KVM'd ADB Bus on the downstream side of it anyway.

 

KBDs seem to be pretty stable on a KVM switch, but the mouse will go wonky fairly regularly. There's a utility called ADB Reset that I use to fix any KVM induced ills on the bus. I keep an alias on the desktop between the HDD and Trash Can for tabbing between desktop icons so I can run it from the KBD whenever the mouse is DOA. I also make sure it's the first hit for A so I can select it easily after control-tabbing through the open apps in the case that the a full screen window covers the ADB Reset alias.

IIRC, that's how to do it, I haven't used the ADB KVM since I moved three years ago and it's been over nine years since it was part of my production setup. YMMV! ;)

 

One day I intend to build an adapter box that will contain the controller from the horrible AppleDesignKBD which should take care of the lack of K&M emulation by keeping the ADB bus active on the console. ISTR testing that out at some point by having that KBD set up in between a Mac and my mechanical ADB KVM switch.

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  • 2 weeks later...
  • 7 years later...

Topics with KVM in title: https://68kmla.org/forums/search/?&q=KVM&search_and_or=or&search_in=titles Lots of places in that list to look for existing KVMs to put on eBay search lists.

 

In this day of 10x10cm boards and 3D printing, I'd love to see someone do an electronic controller for a stack of (eight?) shields to make up a proper electronically gated KVM switch for Macs. The more difficult part would be coming up with a KVM Cable for the setup. @maceffects have you got connections for short run cable builds?

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  • 2 weeks later...

Not sure if anyone else has seen this. I noticed there’s a Shopify storefront at drbott.net that appears to be selling the ADB Moniswitch. Their http://www.duregexpress.com/ site doesn’t appear to ship to the US, but the Shopify site seems like it’s supposed to. However, if you try to checkout, at the final screen PayPal says “This store can't accept real orders or real payments.”

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On 2/22/2021 at 4:16 PM, dontdoxmeman said:

Not sure if anyone else has seen this. I noticed there’s a Shopify storefront at drbott.net that appears to be selling the ADB Moniswitch. Their http://www.duregexpress.com/ site doesn’t appear to ship to the US, but the Shopify site seems like it’s supposed to. However, if you try to checkout, at the final screen PayPal says “This store can't accept real orders or real payments.”

Send them an email, maybe their Paypal account has changed from the one provided to shopify.

 

I won a KVM on ebay a few weeks back (Belkin model for PS/2 machines with cables) and ebay told me the seller cannot accept paypal. The reason was they used a different paypal account then the one they had linked to ebay.

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