The router is a small and fairly generic black box, with no design flair. If you were asked to draw a router, this is what it would look like.
The build quality is good with high-quality plastics that refuse to flex.
The only unusual thing about the design is two feet on the back of the device that help to angle the unit and allow for increased cooling. There is also a stand that lets you position the RT1900ac vertically, but the cables then enter at the top and end up looking quite messy. The front edge has LED indicators for power, Wi-Fi, WAN, and network. There is also a recessed eject button for the SDXC (supports up to 2TB) card slot which is on the right side of the device next to a single USB 3.0 port.
On the back of the device you will find the power switch, three antenna connections and also sockets for WAN, power, and the four gigabit Ethernet ports. The reset button is positioned underneath the back of the device. On the left of the device is a Wi-Fi switch and the WPS button.
Setting up the device is simplified through the use of a smartphone app (DS router), but can also be done by navigating to http://router.synology.com. The process requires you to setup an admin account and enter Wi-Fi settings before deciding if you want to operate in standard router mode, or run the RT1900ac as a access point or wireless client. Settings are saved and the router reboots to give you access to the Synology Router Manager software and desktop-like interface.
I was really pleased to see that Synology require creation of a user account and password during the setup procedure, increasing the security of the router. There are also options to auto-update the software to keep the device as secure as possible.