Anyone?

It is possible but will likely suffer from keyboard shortcuts related issues. Things without keyboard control should behave fine, you just manually press buttons on the devices to change inputs.
Image quality might drop too but that's usually something you can notice only in very high resolutions.

First off, Aten isn't low-end stuff. At least you have two of the best devices in their category to start with.

I hate shortcuts and try to disable them on any stuff I use, so I can 't offer any advice there. As for the image quality bit - that would be my prime concern. VGA is analog, so the signal never gets regenerated between hops, it just keeps deteriorating. Even leaving out the merits of the KVMs themselves and the cables you use, all the connector-air-connector gaps you're introducing here will add signal reflections into the mix. It's true you'll only see that at higher resolutions, but I'd expect to see deterioration at 1024x768 already with a cascade like this. So you can get away with it for DOS, but as soon as you're doing anything with a desktop, it'll hurt.

My advice:
- only cascade DOS or other max 640x480 stuff
- see whatever you Heath Robinson together now as a temporary solution until you find a proper 8-port KVM.

The latter shouldn't be too hard, with servers moving away from VGA now, everyone's dumping their VGA rackmount KVM switches. I picked up two for free over the past few months and now use the better one (an Aten) for my retro stuff. The other is dead btw, a cap blew and took down some other circuitry with it :'(

Contact Aten support. They usually reply within 24 hours and appear to be very well informed. I'm sure they would be able to answer you.

Thanks a lot guys. 😊

Second KVM will be connecting the PMMX and 486 computers to the setup, mostly DOS stuff, so video detoriation would be acceptable I guess. Getting help from Aten is a good idea, I'll try that.

Thanks a lot!

IME, the keyboard shortcuts on most of those inexpensive desktop KVMs were flaky at best anyway. You'll get some analog bandwidth limitation on the VGA, but it should work fine.