Center ID Pin (Smart Pin). This data line identifies the charger's capacity (e.g., 65W, 90W). Connector Pinout Diagram
The communication line that connects to the tiny center pin in the barrel connector. Connector Pinout Diagram 3 Wire Dell Laptop Charger Wire Diagram
If you have a cut Dell charger cable and the colors are faded (e.g., black, black, red), follow this step-by-step testing method. Center ID Pin (Smart Pin)
Some Dell adapters swap positive and negative – before connecting. 3 Wire Dell Laptop Charger Wire Diagram