• Telephone polarity

    From Keith F. Lynch@21:1/5 to All on Sat Oct 30 18:14:34 2021
    I recently got a new Magicjack VoIP device, as the old one had gotten
    flaky after seven years. When I hooked it up, I got a dial tone, but
    the touch tone buttons on my phone didn't do anything except make a
    faint chirp.

    When I reversed the leads inside the phone, it worked fine.

    The new Magicjack device is wired backwards. Aren't all touch tone
    telephones polarized? If so, the new device would get nothing but
    customer complaints, except from the few customers who have the
    knowledge and experience to diagnose and fix the problem.

    And it can't be that most people have rotary dial phones, since those
    won't work at all with Magicjack. (Yes, I checked, years ago.)
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Todd@21:1/5 to Keith F. Lynch on Sat Oct 30 15:05:25 2021
    "Keith F. Lynch" <kfl@KeithLynch.net> writes:

    The new Magicjack device is wired backwards. Aren't all touch tone telephones polarized? If so, the new device would get nothing but
    customer complaints, except from the few customers who have the
    knowledge and experience to diagnose and fix the problem.

    Actually, no; as I understand it,later touch-tone phones had effectively
    a full-wave diode bridge added in to the power-supply circuit for the tone-generator bit so it wouldn't care which way the line was wired.
    For earlier phones Ma Bell and/or AT&T (not sure of the exact timing)
    made a retrofit board called a "polarity guard". AT&T isn't making the originals anymore, but third parties are making and selling knockoffs
    for those with old touch-tone phones. I recently got a couple from this
    guy

    https://www.oldphoneworks.com/polarity-guard.html

    since I have old touch-tone phones and more than once over the years
    I've had issues with the phone line going out and the AT&T repair tech reconnecting the line with a random polarity.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Scott Dorsey@21:1/5 to Keith F. Lynch on Sat Oct 30 20:55:15 2021
    Keith F. Lynch <kfl@KeithLynch.net> wrote:

    The new Magicjack device is wired backwards. Aren't all touch tone >telephones polarized? If so, the new device would get nothing but
    customer complaints, except from the few customers who have the
    knowledge and experience to diagnose and fix the problem.

    Starting in the later 1970s, phones began to have bridge rectifiers installed allowing them to operate with reversed polarity. Earlier 2500s do not have
    a rectifier block, later ones do. Pretty much any phone today has one, and telcos don't worry much about preserving polarity anymore.

    Before swapping the phone, make sure it's not your cable that is wired backwards, since plenty of them swap tip and ring.
    --scott


    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Keith F. Lynch@21:1/5 to Scott Dorsey on Sun Oct 31 18:15:01 2021
    Scott Dorsey <kludge@panix.com> wrote:
    Starting in the later 1970s, phones began to have bridge rectifiers
    installed allowing them to operate with reversed polarity.

    Interesting. My phone dates to 1979, and it definitely has no bridge rectifier. I didn't know any phone did.

    Before swapping the phone, make sure it's not your cable that is
    wired backwards, since plenty of them swap tip and ring.

    I'm using the same cable as with the previous Magicjack unit. So the
    two units are definitely wired in reverse of each other. Of course it
    could be that my phone is backwards. But that would just mean that
    either the cable or the previous Magicjack unit was backwards.

    It's a standard translucent RJ11 cable. Someone would have to really
    work at it to make one of those backwards, since each of the four
    wires goes straight through, and remain colinear, parallel, and flat
    over the whole length.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Scott Dorsey@21:1/5 to Keith F. Lynch on Sun Oct 31 18:39:53 2021
    Keith F. Lynch <kfl@KeithLynch.net> wrote:
    It's a standard translucent RJ11 cable. Someone would have to really
    work at it to make one of those backwards, since each of the four
    wires goes straight through, and remain colinear, parallel, and flat
    over the whole length.

    Unfortunately it's very easy. Just put one connector on upside-down
    and next thing you know, the positions of the red and green wires are
    swapped (as are the positions of the yellow and black). Many of the
    cables you see from china are just put on any which way.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dorothy J Heydt@21:1/5 to Scott Dorsey on Sun Oct 31 19:54:32 2021
    In article <slmntp$p2$1@panix2.panix.com>,
    Scott Dorsey <kludge@panix.com> wrote:
    Keith F. Lynch <kfl@KeithLynch.net> wrote:
    It's a standard translucent RJ11 cable. Someone would have to really
    work at it to make one of those backwards, since each of the four
    wires goes straight through, and remain colinear, parallel, and flat
    over the whole length.

    Unfortunately it's very easy. Just put one connector on upside-down
    and next thing you know, the positions of the red and green wires are
    swapped (as are the positions of the yellow and black). Many of the
    cables you see from china are just put on any which way.

    I'm almost certain I've seen the equivalent (only I think it was
    a power cord that was supposed to plug a computer into the wall)
    on _On Call_ a while ago.

    https://www.theregister.com/Tag/on-call

    Posts (practically) every Friday, always funny even to me who
    don't understand the electronic jargon.

    --
    Dorothy J. Heydt
    Vallejo, California
    djheydt at gmail dot com
    Www.kithrup.com/~djheydt/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Keith F. Lynch@21:1/5 to Dorothy J Heydt on Sun Oct 31 21:29:06 2021
    Dorothy J Heydt <djheydt@kithrup.com> wrote:
    Scott Dorsey <kludge@panix.com> wrote:
    Unfortunately it's very easy. Just put one connector on upside-
    down and next thing you know, the positions of the red and green
    wires are swapped (as are the positions of the yellow and black).
    Many of the cables you see from china are just put on any which way.

    I'm almost certain I've seen the equivalent (only I think it was a
    power cord that was supposed to plug a computer into the wall) on
    _On Call_ a while ago.

    About 40 years ago, my employer had a problem with a new disk drive.
    To their credit, DEC was able to diagnose the problem over the phone.
    The disk was spinning backwards! The cure was to reverse any two of
    the three leads in the 240 volt three phase power.

    I couldn't open the expensive disk drive (more than ONE HUNDRED
    megabytes!) without voiding the warranty. The plug was one-piece
    molded. That left the power outlet.

    There was no way to remove power from the outlet without removing
    power from every outlet in the computer room. I asked the boss when
    I could schedule such a shutdown. The answer was "never."

    So I rewired a live 240 volt outlet. To be fair, it's only 208 volts
    between any two wires.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Gary R. Schmidt@21:1/5 to Keith F. Lynch on Mon Nov 1 12:19:06 2021
    On 01/11/2021 08:29, Keith F. Lynch wrote:
    Dorothy J Heydt <djheydt@kithrup.com> wrote:
    Scott Dorsey <kludge@panix.com> wrote:
    Unfortunately it's very easy. Just put one connector on upside-
    down and next thing you know, the positions of the red and green
    wires are swapped (as are the positions of the yellow and black).
    Many of the cables you see from china are just put on any which way.

    I'm almost certain I've seen the equivalent (only I think it was a
    power cord that was supposed to plug a computer into the wall) on
    _On Call_ a while ago.

    About 40 years ago, my employer had a problem with a new disk drive.
    To their credit, DEC was able to diagnose the problem over the phone.
    The disk was spinning backwards! The cure was to reverse any two of
    the three leads in the 240 volt three phase power.

    I couldn't open the expensive disk drive (more than ONE HUNDRED
    megabytes!) without voiding the warranty. The plug was one-piece
    molded. That left the power outlet.

    There was no way to remove power from the outlet without removing
    power from every outlet in the computer room. I asked the boss when
    I could schedule such a shutdown. The answer was "never."

    So I rewired a live 240 volt outlet. To be fair, it's only 208 volts
    between any two wires.

    Why didn't you just wire up a crossover extension cord?

    And cover it with large red flags &c.

    Cheers,
    Gary B-)

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Keith F. Lynch@21:1/5 to Gary R. Schmidt on Mon Nov 1 03:33:28 2021
    Gary R. Schmidt <grschmidt@acm.org> wrote:
    Keith F. Lynch wrote:
    So I rewired a live 240 volt outlet. To be fair, it's only 208 volts
    between any two wires.

    Why didn't you just wire up a crossover extension cord?

    Good question. I just didn't think of it. Maybe because most of my
    previous electrical work had been hobbyist stuff, and as such I had a
    strong aversion to *buying* anything, rather than working with what I
    had or could find in someone's trash.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)