Right now you have a relatively old display that also happens to use a type of connection that severely limits your options, at least if you're not completely invested in Apple's ecosystem, so I would argue that it wouldn't make sense to buy a new KVM here in late 2019 to accommodate an old, "difficult" display. However, if you do buy a new KVM, I would wait until you first get a new display.
If you only want to run a single display, then your options expand (and become much less expensive), but I haven't done specific research into that. The StarTech unit was cheaper, and normally I would have recommended it because I've had consistently positive experience with lots of StarTech products over many years, but based on some of the reviews I read, they seemed to have missed the mark on that particular product. It came down to the IOGear unit I ultimately recommended and a similar offering from StarTech. When I was researching KVMs for the friend I mentioned above, the fact that he wanted a KVM that would support dual DisplayPort displays narrowed the list of choices considerably. In terms of KVMs, I'm a fan of IOGear because they seem to have KVM design nailed down. You can't run a PCIe peripheral through a USB controller. That's also why external GPU enclosures require Thunderbolt rather than regular USB-C. The reason you're only finding Thunderbolt to PCIe enclosures rather than USB-C to PCIe enclosures is because regular USB-C does not support carrying PCIe traffic. There are no workarounds here, kludge-y or otherwise. Either the display and KVM have to change, or you need to get a Thunderbolt-capable system. That is a majorly limiting factor because the vast majority of KVMs don't support Thunderbolt output for a display, and the ones that do would have to be receiving a Thunderbolt signal from the source system in order to make that work, which you can't achieve with a Latitude 7490 that wasn't ordered with Thunderbolt 3.
I did some research and confirmed what I suspected, which is that the Apple Thunderbolt Display will not accept a garden variety DisplayPort signal. But of course that's a fairly expensive the Thunderbolt Display is the killer here. And then both of the displays he's using have DisplayPort inputs, so that part is easy.
#2017 macbook air docking station Pc
On the PC side, he just runs two DisplayPort cables and a USB cable. On the MacBook side, he connects to a CalDigit TS3+ docking station to maintain single cable connectivity (including power) and then connects the dock's video outputs and one of its USB ports to one side of the KVM.
#2017 macbook air docking station pro
On the Latitude 7490 side, use either a breakout adapter like the DA300 or a USB-C to DisplayPort cable plus a USB cable.Ī friend of mine has the IOGear GCS1942 for his MacBook Pro and a desktop PC. On the MacBook Air side, use either a Thunderbolt 2 to video+USB breakout dongle or a Mini-DisplayPort to DisplayPort cable plus a USB cable, assuming the Air has a regular USB port.
Your only option would be to get a different KVM that had traditional USB and video inputs and then:
The bottom line is that if your KVM only accepts a Thunderbolt 2 connection from the source device, there's no way to get your non-Thunderbolt Latitude 7490 working with it. For another, those adapters would have USB-A ports as found on host devices such as laptops, not USB-B ports as found on peripheral devices (like printers and the USB inputs on traditional KVMs). For one thing, those dongles are only designed to support video output from a Thunderbolt 2 source device, not video input from some other device into a Thunderbolt 2 device. That said, are you considering plugging some sort of Thunderbolt 2 to video+USB breakout dongle into one of the Thunderbolt 2 inputs on your KVM and running separate video and USB cables from your Latitude into that dongle? If so, that's not going to work either. Adapters that can convert a DisplayPort signal to HDMI are quite rare, but USB-C/DisplayPort to HDMI adapters and cables are quite common, and devices that will take a USB-C port and give you both video output connectors and USB ports are fairly common too.