RJ-11 and RJ-45 Modular Plug Tester
    Product # 8138
    RJ-11 and RJ-45 Modular Plug Tester
    Product # 8138
    In Stock This item should ship today (12/8/2016) if ordered within 3 hours 55 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
    96 Reviews
    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1 Star
    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
    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
    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
    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
    Quick Cable tester
    Good cheap tester, every network tech or engineer should have one of these

    PROS: inexpensive, good cable tester, easily tests distant ends of cables

    CONS: Uses 9 V battery, would prefer it used AA
    January 22, 2012
    RJ45 tester.

    PROS: Great RJ45 tester for a reasonable price.
    November 7, 2014
    Worked Perfectly Out-of-the-Box
    Simple, easy-to-use, and inexpensive. What a great buy!!
    July 8, 2016
    Great tool!
    Faithfully checks the continuity of my new CAT-6 cables. Great tool and very much needed to assure the cables are crimped properly and that they work the first time!

    PROS: Bright LED display, connectors clearly indicated. Remote can be removed from the "parent" unit.

    CONS: Lightweight materials seem to imply "cheapness", but the tool works great!
    August 25, 2014
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