Dell UltraSharp 42.51" 4K Monitor - Manual (Page 19)

About your monitor | 19
Pin assignments
DP port (in)
Pin number 20-pin side of the connected signal cable
1 ML3(n)
2 GND
3 ML3(p)
4 ML2(n)
5 GND
6 ML2(p)
7 ML1(n)
8 GND
9 ML1(p)
10 ML0(n)
11 GND
12 ML0(p)
13 CONFIG1
14 CONFIG2
15 AUX CH (p)
16 GND
17 AUX CH (n)
18 Hot Plug Detect
19 Return
20 DP_PWR