Cut the broken part out.

Cut the cable well before the break to ensure that you have a good set of wire ends. Make the cut as straight as possible so that the individual wires are the same length.

Strip the cable cover back on the good end.

Cut carefully along the length of the jacket with a blade, making sure you don’t cut into the insulation of the bundled wires inside the jacket. A good cut length is somewhere between 1/2 and 1 inch. Once you’ve done that, pull the cable jacket apart and peel it back to expose the twisted pairs.

Untwist and flatten the individual wires.