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 (10/28/2016) if ordered within 8 hours 49 minutes

    Volume Pricing (Log In to see Member Pricing)

    Volume Pricing

    Qty: 1 $7.43
    Qty: 2-9 $7.10
    Qty: 10-19 $6.77
    Qty: 20-49 $6.44
    Qty: 50+ $6.12

    To see and take advantage of our member pricing sign up for a business account or contact our sales team.

    Learn more about Monoprice Business

    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

    96 Reviews

    92.29% of the reviewers recommend this product


    Wonderful little device!

    • Anonymous,
    •  Little Rock, AR 
    • 7/31/2016 6:25:10 PM

    This little device is very reasonably priced and works perfectly. I had one before but misplaced it. It will tell you if there is an open circuit in any of your 8 CAT wires and it will tell you if your wiring is not identical on each end. The sequence of the lights should start at the top and come straight down. If one end is misaligned with the other end, the lights on the 2nd end will not progress in sequence from wire 1 through wire 8 like the first end does. Indispensable tool for making or checking network cables or phone lines. Order was processed in a very timely manner and the product was as advertised.

    Was this review helpful to you?

    Worked Perfectly Out-of-the-Box

    • Ed,
    •  Granite Bay, CA 
    • 7/8/2016 12:24:15 PM

    Simple, easy-to-use, and inexpensive. What a great buy!!

    Was this review helpful to you?

    Works Great

    • Anonymous,
    •  Santaquin, UT 
    • 5/2/2016 4:43:15 PM

    Pros: Simple, basic, easy to use.

    Cons: Not very feature rich.

    Very basic cable test, but works great. I had created my own RJ45 ends on Cat6e, apparently I had one wire that was a bad connection, and the tester alerted me.

    Was this review helpful to you?

    Peace of mind for a nominal price

    • JRNorman,
    •  Sugar Land, TX 
    • 4/10/2016 4:21:17 PM

    Pros: Quick and each way to test any Ethernet cable. Best of all it comes in two parts so you can test cables installed in the walls.

    Cons: None that I know of. The construction is a little flimsy but for the hobbyist it should be dependable. Might not last too long for a professional who uses it lot.

    It helped me determine whether the problem I was having was in the Ethernet receiver, the wiring or the router. I would still be scratching my head without it.

    Was this review helpful to you?

    Good value

    • DVACPA,
    •  Plainview, NY 
    • 3/31/2016 11:34:56 AM

    Pros: Small size and case.

    Cons: Light display difficult to read.

    Tester is good for the price.. Lights are a bit difficult to follow.. The light below the indicator light that is one, appears to be on as well. I like the small size and case.

    Was this review helpful to you?
    Tax and shipping will be calculated at checkout