What is the purpose of a cable tester?

Cable testers verify the electrical connections in a signal cable — confirming things are wired correctly between the ends of the cable. If there is a broken connection, the Hosa CBT-500 Cable Tester will let you know exactly where that connection is, which may have a simple solution such as resoldering a single contact point, saving you from throwing out a perfectly good, salvageable audio cable. Diagnosing these issues can help save a lot of headaches in the long run. Always test your cables before gigging, which can be done quick and easy with the Hosa CBT-500.

How to Test an Audio Cable

1. Turn knob to position 1
2. Plug one connector into corresponding jack on the left side of tester
3. Plug other connector into corresponding jack on right side of tester
4. Turn knob to each position to check wiring of each contact

Alternative Continuity Test

For any electronic connection to be tested, a complete loop must be present. The additional continuity testers allow you to test any pin and contact point in order to complete the circuit. These allow you to test the connectivity of any circuit, not just audio cables. To use the continuity testers:

1. Apply the tip of each lead to the corresponding contacts
2. If continuity exists, the tester will beep

Battery Check

Always make sure to check that the battery has life before testing any cables so you don’t misdiagnose any connection as faulty. The steps for the Hosa CBT-500 Cable Tester are simple:

1. Turn knob to battery check
2. The LED will illuminate if the battery is charged

Hosa’s Cable Tester – Better Safe Than Sorry

Hosa’s CBT-500 Cable Tester is constructed from metal to withstand field abuse and operates with a standard 9-volt battery (included). The device also provides a battery check function to ensure proper working condition prior to use. The CBT-500 Cable Tester makes an invaluable addition to one’s ‘tools of the trade’ and is ideal for use when preparing for a concert, studio recording session, or an installation as well as checking cables afterwards in order to ensure working operation the next time. Get yours today.

 

- Hosa

Electronic device used to verify electrical connections

A tester and analyzer for twisted pair and fiber optic cables. A simple tester for BNC and twisted pair cabling

A cable tester is an electronic device used to verify the electrical connections in a signal cable or other wired assembly. Basic cable testers are continuity testers that verify the existence of a conductive path between ends of the cable, and verify the correct wiring of connectors on the cable. More advanced cable testers can measure the signal transmission properties of the cable such as its resistance, signal attenuation, noise and interference.[1]

Basic tester

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Generally a basic cable tester is a battery operated portable instrument with a source of electric current, one or more voltage indicators, and possibly a switching or scanning arrangement to check each of several conductors sequentially. A cable tester may also have a microcontroller and a display to automate the testing process and show the testing results, especially for multiple-conductor cables. A cable tester may be connected to both ends of the cable at once, or the indication and current source portions may be separated to allow injection of a test current at one end of a cable and detection of the results at the distant end. Both portions of such a tester will have connectors compatible with the application, for example, modular connectors for Ethernet local area network cables.

A cable tester is used to verify that all of the intended connections exist and that there are no unintended connections in the cable being tested. When an intended connection is missing it is said to be "open". When an unintended connection exists it is said to be a "short" (a short circuit). If a connection "goes to the wrong place" it is said to be "miswired" (the connection has two faults: it is open to the correct contact and shorted to an incorrect contact).[1]

Generally, the testing is done in two phases. The first phase, called the "opens test" makes sure each of the intended connections is good. The second phase, called the "shorts test" makes sure there are no unintended connections.

There are two common ways to test a connection:

1. A continuity test. Current is passed down the connection. If there is current the connection is assumed to be good. This type of test can be done with a series combination of a battery (to provide the current) and a light bulb (that lights when there is a current).
2. A resistance test. A known current is passed down the connection and the voltage that develops is measured. From the voltage and current the resistance of the connection can be calculated and compared to the expected value.

There are two common ways to test for a short:

1. A low voltage test. A low power, low voltage source is connected between two conductors that should not be connected and the amount of current is measured. If there is no current the conductors are assumed to be well isolated.
2. A high voltage test. Again a voltage source is connected but this time the voltage is of several hundred volts. The increased voltage will make the test more likely to find connections that are nearly shorted since the higher voltage will cause the insulation of nearly shorted wires to break down.

Signal testers

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More powerful cable testers can measure the properties of the cable relevant to signal transmission. These include the DC resistance of the cable, the loss of signal strength (attenuation) of a signal at one or more frequencies, and a measure of the isolation between multiple pairs of a multi-pair cable or crosstalk. While these instruments are several times the cost and complexity of basic continuity testers, these measurements may be required to certify that a cable installation meets the technical standards required for its use, for example, in local area network cabling.

Optical cable testers

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An optical cable tester contains a visible light source and a connector compatible with the optical cable installation. A visible light source is used, so that detection can be done by eye. More advanced optical cable testers can verify the signal loss properties of an optical cable and connectors.

See also

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References

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1. a bUpgrading and Repairing Networks, Que Publishing 2004,

   Terry William Ogletree,, Que Publishing 2004, ISBN 0789728176 , page 961