Has someone detailed intel on DDM in context of KM/KVM switches laying around to throw at me?


Apr 3, 2016
I'm looking for a KM or a KVM switch for me to buy. It shouldn't be pass-through, but should also be transparent to more than your garden-variaty keyboard and mouse. Adder's True USB might do the trick - I don't know - but the switches that bring it are insensibly expensive and I have no need for seemless switching (switching by moving the pointer across the screen border), which there devices bring too and undoubtedly the price tag also. TTU should be ok for me with the keyboard I have now, since my keyboard only uses USB 1.1 protocols for its HIDs, but since every key is backlit by its own RGB-LED it might easily bust USB-1.1's electrical current quota and TTU only talked about USB versions not specifically currents - so I must assume it wouldn't deliver. Plus I might buy keyboards in the future, that want to talk USB 2 (for whatever reason ?)
DDM is presented by users as kind of a general problem solver, but no-one's saying how or to what extent.
My current plan would be to get an old KVM switch model by StarTech, that does DVI and USB with DDM, which still goes for 250 EUR. :/ But, I'd use it for USB only, since its video bandwidth cannot keep up with my monitor. I'd also get a HDMI switch for - as they call it - True 4k. The latter going for 64 EUR and both having a serial interface for commands! Then I'd just need some microcontroller with four buttons to feed their serial interfaces, maybe even put that thing into the StarTech switch to grab the LED states and only make the video switch follow suit instead of me pressing buttons on the microcontroller.

But before I throw that kind of money at a KVM switch, that I'll only ever use as a KM one, I'd like to be very sure, that it'll do. Has anyone experience with those DDM thingies? It would be great, if it can pump out some current, though if need be an Y-cable could help out there. But how would it handle a keyboard, that registers as one (or two, because of N-Key Rollover?) keyboard, a mouse, and a COM port (in terms of USB, a communication device and a communication control device)? Would it ignore the COM port and mouse, and support the keyboard however strange it is? Or would it even pass through the parts it doesn't care for itself at its keyport port? Or would it go on strike and thus my keyboard not work?
Any profound intel on this matter would be greatly appreciated.