RJ-11 and RJ-45 Modular Plug Tester
    Product # 8138
    RJ-11 and RJ-45 Modular Plug Tester
    Product # 8138
    In Stock This item will ship on 1/23/2017 if ordered within 1 days 2 hours 17 minutes

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    RJ-11 and RJ-45 Modular Plug Tester

    This Monoprice RJ11/RJ45 tester is a simple, yet powerful, tool that helps troubleshoot network and telephone cables for broken wires and crossed connections.

    The tester consists of a main Master unit and a detachable Remote unit, each of which have an RJ11 and an RJ45 jack. The unit is powered with a 9-volt battery (not included) and can be stored in the included, zippered, synthetic leather case.

    The Master and Remote unit each have a series of 9 LEDs that show the status of each line on the attached cable. The tester supports both a fast automatic and a slow automatic mode.

    The following operating instructions supercede the instructions contained in the enclosed operator's manual.

    To test a cable:

    1. Insert one end in the appropriate jack on the Master unit and the other in the same type jack on the Remote unit.


    2. Move the tester power switch to the "On" or "S" position. For best results, use the Slow Automatic mode (S position) to perform the test, as this gives time to watch the light sequence and ensure that the same LEDs illuminate on the Master and Remote simultaneously.

    3. Watch the LEDS on both the Master and Remote units. Under normal conditions, using a straight-through RJ45 cable in good condition, the LEDs will simultaneously illuminate in the sequence 1-2-3-4-5-6-7-8-G on both the Master and Remote units.

    4. A faulty or miswired connection will produce a different result, as follows:

      1. If there a wire is broken or otherwise not connected the LED on the Master unit will illuminate, but no LED will illuminate on the Remote unit.

      2. If a wire is crossed, different LEDs will illuminate on the Master and Remote units. For example, if the 3rd LED on the Master unit and the 5th LED on the Remote unit both illuminate then the wire is crossed between pin 3 on the Master side and pin 5 on the Remote side.

      3. If there is a short circuit between two or more wires, no LEDs will illuminate on either the Master or Remote unit.

    Note that when testing RJ11 or RJ12 cables with a 6P6C connection, only the LEDs 1-6 will illuminate. If using a 4P4C connection, only the LEDs 2-5 will illuminate.

    This product requires a 9 volt battery, which is not included!

    Support Files:

    Package Contents:

    • 1x Cable Tester Master unit
    • 1x Cable Tester Remote unit (attached to Master)
    • 1x Synthetic leather, zippered carrying case
    4.7 / 5.0
    100 Reviews
    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1 Star
    Worked great at first...
    I bought this 2 months ago and started using it last week while making keystones for a house rewire... it worked great the first week, but yesterday I was making a jacks and during a test, the LED skipped pin 3 (usually means pin 3 is bad) so I proceeded to spend over an hour of my time troubleshooting, I replaced both ends of line twice and then started looking for any damages to the cable along the way, after finding nothing, it finally dawned on me that just MAYBE it was the tester. I took a premade cat 6 cable I bought from monoprice and sure enough it skipped LED 3, the entire time it was the tester, not the cable or keystones. Do yourself a favor and check your tester before each use to make sure its functioning properly or you make lose a lot of time troubleshooting something that isn't faulty.

    PROS: Cheap price, easy to use

    CONS: no coaxial/rg6 tester, low reliability, used 9v battery instead of AA.
    April 23, 2015
    Response from Monoprice
    Hi Bruce,

    Thank you for your review and bringing this to our attention. I will be informing our product managers as well as submitting a complaint regarding this issue. For now however, I can assist you in setting up an RMA for a replacement to see if that will work better for you. We do offer a 30 day return policy as well as a one year warranty on this item. Obtaining a replacement will be of no additional cost to you. Please let me know if you would like to continue with a replacement and I can get that started for you right away.

    Gisselle B.
    Tech Support
    November 18, 2016
    Monoprice Administrator M
    inexpensive and works great
    had network issues for a long time lost/no connections and 10mb connections instead of 1000mb connections. plugged this tester into the internally-wired network cables and turns out the internal wiring was crossed giving out a signal like 36145278 instead of the 12345678 that showed up on a short cable i had lying around.

    had the electrician re-wire the entire house on his dime. money well spent on my part. wished it used aa or aaa batteries instead of 9v ...

    PROS: simple design


    easy to use

    CONS: needs 9v battery
    January 26, 2015
    Pleased with Purchase
    I don't often need this tester, but, it has come in very handy on a couple of occasions in the last two months. I set up computers on a part-time basis for a few small clients. Every once in a while, I have needed to check the integrity of cables. In the past, I did this with an ohmmeter, because I was not willing to spend the $50 or more that other cable testers cost. While my old method worked, it was a real pain.
    When I saw this tester, I decided to throw it in with another order. I am very glad I did. A month ago, I got a call from one of my clients asking me to check out why he could not get a computer on to his network. Using this tester, I was able to verify that all of the cables were good within a couple of minutes, so I could eliminate that as a cause very quickly. I ran into a similar situation for another client last week. This tester allowed me to isolate a bad cable quickly, and get the computer involved back on line in minutes. So this tester not only saved me time, but also made me look very professional.
    The only drawback is that it needs a 9 volt battery. Not a real big deal, but, I just need to remember to check that the battery is good before going out on a service call. It would really be nice if it had a USB input to tap power from a nearby computer, just in case I arrived at a service call with a dead battery.
    Overall, for the low price and time savings, this has been a terrific purchase.

    PROS: Low cost
    Easy to use

    CONS: Needs a 9V battery
    November 17, 2011
    Excellent little unit. Tested a cable successfully. The passive (unpowered) part of the tester slides on and attaches to the main tester to keep the 2 sections together, which I like, and the tester also has a decent carrying pouch. I really like the On-Off switch to turn the unit completely off when not in use, so conserve battery life. Overall I am extremely pleased with the value for what it is and what it does. It's simple but very inexpensive and it works.

    PROS: Very easy to use and functions well for what it's needed for, which is the test continuity on all 8 pins. I don't have a shielded cable to test, to verify that it also successfully tests the ground connection, though there is an LED on the tester for the shield or ground.

    CONS: None so far. Only thing to keep in mind is, if you purchase ANY simple tester like this, if you are by yourself you have to start the test at one end of the cable and go to the other end to see what the test result is on that end. It's fine, just something to keep in mind. If you want something where you go attach one end to a cable, go back to the main tester unit and see the test result from one end to the other (and back again), you'll need to spend considerably more money.
    February 18, 2015
    Well worth the price
    As mentioned by previous reviewers, this thing does not come with the 9V battery. I just rewired my whole house (RJ45 and RJ11 connectors) and this thing helped me out a lot in figuring out which wires were not done properly. Highly recommended.

    PROS: Works great!

    CONS: Nothing.
    March 6, 2012
    basic and easy to use.

    PROS: does the job

    CONS: none
    February 24, 2014
    Easy to use
    I got this to try to re-link the lines on a old house that I recently bought. It was a mess... the house has 15 lines. I am not a professional but using this tester made the job really easy, I had everything figured out in a few hours. And plus the costumer service and the shipping from Monoprice its one of the best I have ever seen, apart from its incredible prices. It shipped immediately and they even sent me a picture with the package in my front door as a proof of delivery.
    February 6, 2012
    Checks connectivity

    PROS: Cheap and gives you confidence in your wiring.

    CONS: Does not test for speed for that you need a much more expensive tool.
    July 27, 2015
    worked great for me
    Good value. Worked great on my RJ-45 cables. Have not tried RJ-11, but no reason to think it wouldn't work equally as well.
    January 15, 2017
    2 weeks ago
    Great Little Tester
    Good Device for testing your LAN and Phone cable to be sure of mismatches or broken wires. Probably going to buy more for work.

    PROS: Great tester for the price- Can't find anything wrong in the first few days of using it. I need to buy one for the workplace now...

    CONS: None so Far.
    June 25, 2014
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