Reminder: There can be different voltage potentials in the grounds at points separated by a large distance.

Not saying this will cause you any trouble or even concern, just a reminder that ‘ground’ in one place may be a different voltage than ‘ground’ somewhere else.

CAT5/whatever is twisted pair without a specific ‘ground’ reference but some outdoor/burial dated cables may also have a ground wire or shield. If that shield is grounded at one end, you may or may not want to also ground it at the other.