open the tops of those 2 connectors on the right side of the NID, and you will see a standard telephone jack, you can plug a standard line cord directly into... this will disconnect the inside wire going into the house, so whoever is inside will not have dial tone while you are connected here... if wanting to monitor the line, then opening the black nut on the left side of the box will provide you access to the drop wire, where you can connect your alligator clips to the gel-filled connector...