I have a Pluggable USB-C dock that I want to use with a Dell Latitude 7480. For two of the monitors I have Dell P2414hb; for the third monitor I have an older Dell P1911 monitor. So far as I know, none of the monitors are 4K support. I can successfully wire any of the monitors to the VGA or standard HDMI port and see content displayed. However, when I try to connect any any of the DVI ports on the monitors to the HDMI 4K port using a HDMI high-speed cable, I don’t see any content displayed on that monitor.
Do I need to purchase a 4K monitor to make use of the third available port (I had hoped to be able to use one of the monitors already in place, although with equivalent or slightly degraded content display)?