Line modes… Most modern DECT 6.0 phones have this buried deep in their internal phone system menu. The factory-default setting can affect your phone’s reliability on numerous levels. But what is line mode, and how does it affect me?According to a support phone call I had with Panasonic, technical quality is affected by the line modes A and B.  When I asked, I was hard pressed to a get a firm technical answer as to how or why there would be a line mode A and B. The support representative wanted to keep it simple by saying it affects sound quality — that sometimes a cord or line sounds staticky. Changing the line mode can make a difference. So I explained that most people want the call quality to be as clear as possible, so merely saying it affects call quality doesn’t really answer the technical question as to why there would even be a line mode A or B.

If you don’t want to learn more about the technical aspects and you just want to “get that blessed phone working”, suffice it to say try both settings and see which one works best for you. Under most circumstances, it is suggested to leave on “Line Mode B”. The below images show how I navigated to the correct setting for my phone.

Press "Menu"Press up arrow until you see "Initial Settings".Press "Select" on "Initial Settings" pane.Press up arrow until you get to "Set tel line".line-mode-settings-05Scroll to and "Select" "Set line mode"Scroll to line mode B and press "Save".Select "Off"Done.

For the rest of us, let’s carry on.

According to one on-line source for a university PBX system, line mode may have something to do with power supplementation. If your phone system is low voltage (like magicJack) you probably should use mode B. If your house has a Network Interface Device outside your house where you can plug in a trimline phone without a any power and the phone works, you probably have a POTS line or “Plain Old Telephone System” line.  If your phone is connected to router perhaps a UVerse modem/router then you are certainly not using a POTS line.

According to another Panasonic source, if you cannot see “Line In Use” when someone else is using one of the other handsets configured to the use same base set, it might help to change the line mode to the alternate setting.

The Ringer Equivalency Number (REN) ends with a B for almost all new model phones, Panasonic or otherwise, so it seems very likely that line mode “B” is somehow integrated or connected with the B at the end of the REN.

While my phone call with Panasonic was not very useful, I found these helpful links.

Helpful links:

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  1. mi opinion muy bueno majick jack con una opsion mas de alimentacion de corriente /? solo que tiene una inconbenensia majick jack es la corrirte de alimentasion que es muy inportante para su funsinamiento sin corriente pues no funciona lojico verdad mi pregunta es podria trabajar con una pila pequena instalandola dentro del mismo equipo de majick jack para que se alimente por si mimo el equipo a la cual se conecta el majick jack eso seria una marabilla y eliminaria la conecsion directa a un toma corriete de casa o de computadora cuando no tengas modo o un lugar de electrisidad sin quitarles sus funciones actuales //? mi punto directo es si majick jack funcine asi creo funcione con una bateria con esa opsion integrada con esasas mismas dimensines del tamamo del majick jack ? solo que tienen que aser es trabajar dentro de la misma cajita de donde se ensambla sus partes y conecsiones de majick jack y aser un puente que se conecte la corrietente de la bateria y trabajaria perfectamete majick jack seria completo y lo podria tener asta en mi bolsa y llebarlo en todo momento conmigo y hablar desde cualquier parte o lugar espero me comuniquen por mi opinion grasias y felisidades por su invento grasias

    1. Carlos,
      I’m not really sure I follow you, because my Spanish is bad, and “Google Translate” is terrible with local expressions and apparently doesn’t correct misspellings in Spanish. I wish I could be more help.

      I assume you like your magicJack, but that you would like to configure your setup so that you can use a battery somewhere in your configuration either while traveling or at home. I’m unclear.

      Perhaps someone else may respond accordingly, though I prefer the response be in English, because I want to be sure I understand what’s being communicated on my website.
      Best of luck,

  2. How can I change the redial settings so that the phone does not store all the numbers dialed, but only the main number. When I redial the calls do not go through because of having so many numbers. it gives a voice error.

    1. The magicJack device does not keep a record of your calls. At least they don’t show any phone record history to me when I log in at their website. This is an issue with your phone that you bought separately and connected to your magicJack. I would Google the model number of my phone and download a copy of its instructions. From there, you should be able to determine how to use the phone’s address book and redial functions.

      Good luck!

  3. My phone calls are constantly dropping for no apparent reason, could the line A or B have any affect on that problem.

    1. You probably should use Line Mode B. It’s unlikely this is the cause of your calls dropping. If you are using a VPN or Proxy server, it’s possible your device’s services are being put through too many hurdles to complete the call. Your IP suggests this is what you’re doing. Perhaps you should unblock your router at least for this service, and that will give you a more stable connection to magicJack’s SIP servers.

      Good luck!


  4. I think Line Mode is to do with DC resistance when hung up.
    This is from the information about it affecting hang up and callerID (part of ring signal. ), which coincide with the on hook resistance.
    telstra touchfone has a switch, from standard to 600 ohms or thereabouts.

  5. It IS about the impedance when on hook.

    The problem is, having devices in parallel on the line ? Whats the impedance ? way down !.
    And so the options of having a high impedance and then the total impedance complies with standards.
    A normal, B High
    OR uniden uses
    0 normal
    1 for medium high
    2 for very high

    touchfone probably has the switch for 1600 ohms, or thereabouts, now I read about this idea.

  6. REN = “Ringer Equivalence Number”
    On an POTS line system, that means how many mechanical ringers the available current from the line coming into your house. The standard by Federal Regulation is/was FIVE old-fashioned, 100% unassisted, analog phone (or other things like modems and FAXes).
    “The ringer equivalence number (REN) is a telecommunications measure that represents the electrical loading effect of a telephone ringer on a telephone line.”

    It appears that A & B selections represent a choice between two different loads that your cordless phone places on the line, so as to conform to the number of phones in your house, and the operating power supplied to your house by your phone company.

    1. If the directions here are not useful, please log in at and talk with the chat agent. Best of luck!

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