Mercury - CAN Data Harness (10-Pin, One Resistor) 30-Foot SmartCraft Lead 84-879980T30. Overview. Large helms and long rigging runs often need more than just extra cable-they need a clean termination point built right into the harness. The Mercury 84-879980T30 CAN Data Harness provides thirty feet of SmartCraft cable with a single integrated resistor, giving the network both the reach and the proper end-of-line load it needs for reliable communication. It carries CAN P, CAN X, and CAN H signals