What Are Cable Testers and Tracers? Types and Selection Criteria
A cable tester checks the wire order and continuity of a data cable; a cable tracer follows the signal a transmitter puts on the line with a receiver to find the right cable.
Cable testers and tracers do two jobs. A cable tester checks that the cores of data, telephone and signal cables are connected in the right order and without breaks. A cable tracer follows the signal that a transmitter puts on the cable with a receiver, to find the right line in an unlabeled bundle or inside a wall. They are used in structured cabling to check RJ45 terminations, to look for breaks and shorts, and to trace lines.
Types
| Type | What it does |
|---|---|
| Cable tester | Shows wire order, open circuits, short circuits and crossed pairs between the main unit and the remote unit with LEDs |
| Tone tracer | The transmitter puts a tone on the line; the receiver probe finds the cable carrying it in a bundle or in a wall |
| In-wall cable and fuse finder | Follows the signal of a transmitter connected to the electrical installation inside walls and in the fuse box |
| TDR cable tester | Measures cable length and the distance to a fault from the reflection of a pulse sent down the cable |
Selection criteria
- Connection to be tested: The UT681L suits RJ45 and RJ11, the UT681C adds BNC coax with its adapter, and the UT681HDMI is for HDMI cables. The UT681L and UT681C also distinguish shielded from unshielded Ethernet cable.
- Need for tracing: Finding the right cable in an unlabeled bundle needs a tone tracer. The UT683KIT traces RJ11 and RJ45 lines and also tests the connection. The UT682 works on LAN, telephone, coaxial and electrical cables; the UT682D on telephone lines, twisted pair and electrical wire.
- Length and fault location: Finding where along the cable a break is, or measuring the cable length, needs TDR. According to the manufacturer the UT685B KIT measures from 2.5 to 500 m, detects PoE power on the line and also traces tone with the receiver in the kit.
- Live lines: Data cable testers and tone transmitters are for de-energized lines. To find an electrical line inside a wall, or the fuse it is connected to, choose a finder designed for electrical installations such as the UT25CL.
- Power supply: The UT681 series and the UT682D run on a 9 V battery, the UT683KIT on a 1050 mAh rechargeable lithium battery. For long days on site, plan for spare batteries or charging.
Common mistakes
- Taking a cable tester for a certification tester: A cable with correct wire order and continuity may still fail the speed and performance requirements of a category such as Cat6. Category performance is measured with a cable certification tester.
- Connecting the transmitter to a live line: A transmitter designed for de-energized lines can be damaged. Before connecting, switch off the circuit and confirm there is no voltage with a voltage and continuity tester.
- Testing without unplugging the cable: While one end is plugged into a switch or a computer, the remote unit cannot be connected; free the cable at both ends.
- Terminating the ends with different pinouts: If one end is wired T568A and the other T568B, the tester shows crossed pairs. For a straight cable use the same pinout at both ends.
Cable testers and tracers in the catalog
The Cable Testers and Tracers category has 9 active products: Unit 8, Schneider Electric 1.
| Model | Type | Connection and cable |
|---|---|---|
| UNI-T UT681L | Cable tester | RJ45, RJ11 |
| UNI-T UT681C | Cable tester | RJ45, RJ11; BNC with adapter |
| UNI-T UT681HDMI | Cable tester | HDMI |
| UNI-T UT683KIT | Tone tracing and connection test | RJ45, RJ11 |
| UNI-T UT682 | Tone tracing and test | LAN, telephone, coaxial, electrical cable |
| UNI-T UT682D | Tone tracing and test | Telephone line, twisted pair, electrical wire |
| UNI-T UT685B KIT | TDR and tone tracing | UTP, FTP, coaxial; 2.5–500 m length measurement |
| UNI-T UT25CL | In-wall cable and fuse finder | Electrical installation |
| Schneider Electric IMT23106 | Tone tracing | De-energized cable; RJ11, coaxial and crocodile clip adapters |
Fiber optic cable carries no electrical signal, so it cannot be tested with these instruments; for visual fault locators and power meters see the Fiber Optic Testers category. The Cat5e, Cat6 and ready-made patch cables you will test are in the Ethernet LAN Cables category.
Frequently asked questions
What is the difference between a cable tester and a cable tracer?
A cable tester checks the two ends of a cable against each other and shows whether the cores are connected correctly. A cable tracer finds where the cable runs or which one it is in a bundle. Models such as the UT683KIT and UT682 do both.
What does a "crossed" result on a network tester mean?
It shows that pairs are connected to different pins at the two ends. The most common cause is one end terminated to T568A and the other to T568B. If a straight cable is wanted, both ends are re-terminated with the same pinout.
Which instrument shows the cable length or where the break is?
A tester with TDR. In the catalog the UNI-T UT685B KIT has this feature; LED testers only show which core has the fault, not where it is.
Can a cable tracer be used on a live electrical line?
Tone transmitters designed for data lines must not be connected to live circuits. To find lines and fuses in an electrical installation, use a finder designed for the job such as the UT25CL and keep to the voltage limits in its manual.