RE: Monitor (UP2516D ) with Laptop Latitude e6440 and Docking station K09A no mDP signal
List all of the numbers you see on the dock labels. List all of the ports on the rear of the dock.
The 2013 Latitude E6440 has the following video out ports = VGA, HDMI The 2016 UP2516D has the following video in ports = HDMI/MHL 1, HDMI/MHL 2, DP, mDP
First, I would remove the dock from the troubleshooting. Connect in this way =
Latitude E6440 HDMI out port --> HDMI to HDMI cable --> UP2516D HDMI 1 in port
Press the UP2516D Input Source button and choose HDMI/MHL 1. If you get the Windows desktop to appear on the UP2516D, then we know that the UP2516D is functional. Post your results. Then we can try to troubleshoot adding the dock.