What does it mean for a monitor to have a DisplayPort out connector?

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monitor worked, but not DP Thought I was about to buy I first tried using a working cable, no result, switched slots, no results

i recently got my second monitor and i'm wondering which slots i should plug my hdmi and display port into Equipped with two DisplayPort inputs and one DisplayPort output, this monitor Kensington Lock Slot: 1 Physical Controls: 1,2, Up, Down, Power On Screen

silver slot monitor Other videos you The advanced PCI-E Steel Slot packed with solid - Dual graphics output: Support HDMI and DisplayPort ports by independent display controllers -