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ADB Switch
Posted by: turbo on 2016-10-09 16:52:20
I'm looking for a way to switch a single ADB keyboard/mouse between a couple of Macs and a IIGS.  Is this a thing?

I was looking on eBay and found this s-video switch.  Any reason something like this wouldn't work (accepting of course to NOT switch the devices while anything is on)?

http://www.ebay.com/itm/4way-Port-ABCD-manual-switch-box-SVHS-S-Video-Super-VHS-4pin-DVD-HDTV-PC-TV-Out-/122147640900

Posted by: beachycove on 2016-10-09 17:47:24
That looks to me like an acceptable approximation to the kind of KVM that you need.

Posted by: mrpippy on 2016-10-09 22:42:34
There's been some other threads about using S-video switch boxes for ADB, and I'm not sure anyone has had success with it.

https://www.thinkclassic.org/viewtopic.php?id=633

http://www.applefritter.com/?q=node/6348

Posted by: turbo on 2016-10-10 09:44:48
Thanks -- I've cast enough doubt on the s-video switch to not try it.  Wound up at a LEM page about the Dr. Bott MoniSwitch device:

http://lowendmac.com/1998/moniswitch-adb-a-kvm-for-adb-macs/

Dr. Bott looks like it is still in business but they only reseller they list doesn't appear to ship to the US.  Anyone familiar enough with this to know how to get one here?

Posted by: beachycove on 2016-10-10 12:00:27
It looks like an ADB switch to me!

I do, however, have a spare ADB/DB15 KVM that I could sell you (pm me). Works fine, but is not suitable for large screens. Perfect for 640x480 or similar.

Shipping from Canada would not be cheap, plus, you'd need adb and DB15 cables. I could supply the works, but this would add to price and shipping.

Posted by: Unknown_K on 2016-10-10 13:18:42
Even if Dr.Bott would ship to the US the ADB KVM has been discontinued ages ago and is probably out of stock.

They don't show up on ebay much either.

Posted by: register on 2016-10-12 14:11:05
The ADB is tough. You might easily build a switch using any multipole switch with at least 4 independent contact sets. A switch for RS232 connections would do well after some rewiring. Just install appropriate mini DIN 4 pole connectors and you are ready to go. As the ADB supports parallel connection of multiple devices (up to eight devices), you might install two or more connectors for keyboard and mouse to your switch, and only one for each computer. Be aware of the fact that in a running Mac removal and reconnection of an ADB mouse will set the mouse pointer speed to minimum - a reset of the ADB might be desired, afterwards. In case you would like to perform a software reset of the ADB (without a need to restart the machine), use the free software »ADB reset«.

Posted by: Unknown_K on 2016-10-12 14:20:16
Connecting and disconnecting the ADB bus (especially if you have multiple devices on it) will cause voltage spikes that are probably not good for the ADB bus (blown fuses). The decent KVM buffer the lines.

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