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Solve this Electronics Mystery

  1. Jun 18, 2009 #1
    Solve this Electronics Mystery!!!

    Hey guys - I really need some help from you experts. My elderly mother and father-in-law have two electrical devices that are, for unexplained reasons, totally incompatible with each other. I need some ideas to identify solutions for this bizarre problem.
    1. The first device is a Philips Lifeline. This is basically a medical emergency system. You push a button on a device around your neck, which activates a speaker phone that calls for emergency services. Other than in an emergency, it should not be placing any calls.
    2. The second device is a Landel Mailbug. This is basically a low tech email system. Periodically, this system will call an 800 number and download or send any emails.
    3. Each device is plugged into a 2-way telephone splitter that connects into the same phone jack.
    Now, the Lifeline was installed two weeks ago. Ever since then, the Mailbug has been very undependable. It may be several days before it will download or send messages. When we contacted Landel, the mailbug company, they confirmed that they are aware of an incompatibility issue with Lifeline. However, even their techs are clueless as to why it's happening. Lifeline is not aware of any problems.

    SO --- can any of you electrical experts explain to me how this could be happening? I'm not an electrical engineer, but I was hoping that one of you could give me some ideas as to how to fix this problem.

    HELP!!!
     
  2. jcsd
  3. Jun 18, 2009 #2
    Re: Solve this Electronics Mystery!!!

    is it possible the Landel Mailbug requires a filter, as it is passing data? Much like a broadband DSL line uses a filter on a phone line. Although, in DSL the filter is used to filter out the higher frequencies of the data so that there is no interferece with voice transmission.

    just a thought :redface:
     
  4. Jun 19, 2009 #3
    Re: Solve this Electronics Mystery!!!

    Does the Landel Mailbug work ok with other phones on that phone line? Do other phones on that line work ok with the Philips Lifeline connected?

    First I would disconnect the Philips Lifeline and check if the Landel Mailbug again works correctly.

    If so, I would check the voltage on the phone line to verify if it is about the correct voltage.

    Then I would reconnect the Philips Lifeline and see if the phone line voltage changes, it shouldn't.

    Does the Philips Lifeline have a test number that you can call to make sure it is operating correctly without calling an ambulance? If so, I would check it with the Landel Mailbug connected.

    Have you considered what would happen if the Philips Lifeline tried to make an emergency call exactly when the Landel mailbug was dialing out?
     
  5. Jun 19, 2009 #4

    berkeman

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    Staff: Mentor

    Re: Solve this Electronics Mystery!!!

    Maybe consider having a 2nd phone line/number activated for the house. It uses the existing wiring (there are 2 twisted pairs in most phone installations in homes), so all you have to do is have the phone company activate the 2nd line (youneed to pay extra on your phone bill, but generally it isn't too much).

    Then, you use a different kind of splitter to split the 2 phone lines at the jack -- it just connects to either one of the two pairs in the jack. This also rules out the problem that skeptic2 alludes to, where an e-mail exchange could block an emergency call for some amount of time.
     
  6. Jun 19, 2009 #5
    Re: Solve this Electronics Mystery!!!

    Thanks for all of the ideas. Here is an update to your questions and ideas.
    1. The manufacturer does not provide or mention a filter, so I doubt it. But, who knows. If I can put my hands on a DSL filter, I'll give that a shot.
    2. Unplugging the Lifeline does "fix" the Mailbug.
    3. There is a way to test the Lifeline. We'll do that at our next opportunity.
    4. The Mailbug is supposed to disconnect automatically whenever someone is on the line.
    5. Checking the voltage is an interesting idea. So, if the voltage is different, how do I fix that?
    6. The house is probably 40-50 years old. I doubt it is wired for two phones. But, I did consider adding a second phone.
    Do you think moving one of the devices to a different phone jack would make a difference? I doubt it.
     
  7. Jun 19, 2009 #6

    berkeman

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    Staff: Mentor

    Re: Solve this Electronics Mystery!!!

    Depending on your area, the phone company may have at least terminated the in-house wiring at an exterior phone box. Around here, the phone company has a policy of debugging phone problems up to that box, but beyond that box, it's your responsibility (they will help for a fee of course).

    So if you have such a box, you can look at it to see if there are two twisted pairs terminated there. If so, it's much easier for the phone company to activate a 2nd line. Most phone cables for in-home use have had at least two twisted pairs in them for a pretty long time, I believe.
     
  8. Jun 20, 2009 #7
    Re: Solve this Electronics Mystery!!!

    Maybe the Lifeline is doing also going off hook occasionally to verify that the line is live and this could be disturbing the Mailbug. Measuring the line voltage with and without the Lifeline attached would tell you if the Lifeline is pulling the line down.

    One thing I don't understand is if the Mailbug is in the middle of downloading mail and the lifeline goes off hook, how does the Lifeline or any other phone get a dial tone? The Mailbug may have hung up but only after it detects another phone going off hook. At no time has the line been disconnected between calls.
     
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