A method of inserting color coded wires into a multiple position modular registered jack connector of a telephone connection interface is disclosed. Individual wires that have been exposed by stripping the insulator covering from the end of a phone line are arranged by color in a wire insertion tool having a wire insertion end and pin depression member and grooves on a top surface that are also color coded in an order representing the order in which the ends of the color coded wires are to be placed into the modular registered jack connector. The grooves are dimensioned to receive in a frictional fit the respective color coded wires of the phone line. The wire insertion tool is moved manually into position such that the ends of the wires extend beyond the wire insertion end of the wire insertion tool and are aligned with conductive pins and associated teeth that pierce the insulation on wire, and the associated slots. The wire insertion tool is pushed straight toward the modular registered jack connector for inserting the ends of the wires into the respective slots such that the pin depression member depresses the conductive pins and the ends of the wires engage the conductive pins and associated teeth such that the insulation of the ends of the wire is pierced. The wire insertion tool is then removed from the color coded wires after the ends of the wires are received into the modular registered jack connector.