On the XPS 15 9550, can an external monitor with Displayport inputs be connect directly into the laptop's USB-C Thunderbolt output using a straight miniDisplayport-to-Displayport cable? Similarly, can a miniDisplayPort to VGA adapter cable be plugged directly into the USB-C Thunderbolt port to drive older monitors/projectors? Or is the TB15 Dock mandatory in order to get the computer talking to external video devices through its Thunderbolt port output?
Additional info ... monitor is a Dell U2713H. Can it be connected to the XPS 15 via a USB-C/Thunderbolt 3 to Display Port cable without the need for a dock or other adapter?
It's supposed to but it is not going to work. The XPS 9550 is defective out of the factory. The USB-C/Thunderbolt 3 port does not work. You can try to get a return but I would recommend you get a refund for your hard earned money and go with HP or ASUS. Their ports are having zero issues.