Which of the following tools would a technician use to determine if a CAT6 patch cable has an open or short?

An OTDR (Optical Time Domain Reflectometer) is used exclusively for fiber optic cables to locate breaks or measure loss, and cannot test copper cable conductors.

A cable tester sends a signal through each wire pair of a copper cable and checks whether continuity is present on all expected pins, flagging opens (broken conductors) or shorts (conductors touching each other). It is the standard tool for verifying that a patch cable is correctly terminated and electrically sound. Many cable testers also detect miswires and split pairs.

A toner probe is used to trace and locate a specific cable run through walls or patch panels, not to test electrical continuity or identify opens and shorts.

A protocol analyzer captures and decodes network traffic at the packet level and cannot perform physical-layer cable continuity tests.