Is it possible to use a USB-C extension cable with the DA200 Adapter? I haven't got much room on my desk so I'd like to move this to behind my monitors. I've tried with the one USB-C extension cable already and this hasn't worked so I was wondering whether I need a particular type?
You'd need a USB-C cable that supported at least USB 3.1 Gen 1 traffic, maybe even 3.1 Gen 2. I would get the latter just to be safe, although that will limit your maximum cable length. Some USB-C extension cables only support USB 2.0 because they're primarily intended to be used for charging and maybe some data transfer where bandwidth isn't as much of a priority, but such cables will not only slow down the USB and Ethernet connections on the DA200 (if they worked at all), but they would also lack the necessary wires to carry display traffic, which uses the USB 3.1 wires. For gory details on the vast variations of USB-C and Thunderbolt cables, check out my post here: en.community.dell.com/.../20017817
Strange, I just tried actually searching Amazon for USB-C extension cables, I can't find a single one from a well-known cable manufacturer like StarTech, CablesToGo, Belkin, Anker, etc. They all make regular USB-C cables, but not extension cables.
Just as a possible alternative since it sounds like you're using your DA200 in a more permanent setup rather than carrying it around with you, you may want to consider the WD15 dock instead. It does cost more and it's larger, but it also gets you more built-in USB ports, support for dual displays, and the ability to charge your laptop over the USB-C cable rather than having to connect the power adapter separately. It's sold with either a 130W or 180W power supply, and whether you require the latter depends on which system(s) you'll be using the dock with. Or since they're the same price, you could always play it safe and get the version with the 180W adapter, with the only downside being that the adapter is physically larger and heavier, but if it will be sitting on the floor under your desk anyway, that may not be an issue.