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Phone problems after thunderstorm

Discussion in 'Electronic Basics' started by Mike S., Sep 1, 2008.

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  1. Mike S.

    Mike S. Guest

    I am trying to help my grandmother with a phone problem. I'm not
    entirely sure what's going on (she's very confusing) but some
    (possibly all) of the Caller ID displays on her home telephones are
    garbled to the point where they're unreadable. I think it happened
    after a thunderstorm where the electric went out. The phones work fine
    except for the displays. It's on both the cordless and corded phones.

    Is it at all possible that the storm would damage only the displays on
    the phones but yet the phones still work fine otherwise? I can't be
    sure, but I think even the cordless extension sets that aren't even
    connected to the phone line have the garbled display. That seems
    really strange to me.

    I think the displays on at least five phones are damaged.
     
  2. Phil Allison

    Phil Allison Guest

    "Mike S."

    ** You need to go to her house and get the real facts.


    ** More likely storm water has got into the wiring ( anywhere from the
    exchange to the house) and is causing signal loss & noise on the line -
    that will screw up caller ID.




    ...... Phil
     
  3. Chris

    Chris Guest

    Try borrowing a known good caller ID phone and take it over to
    granny's house. I'd guess it doesn't work, either. Sounds like
    something's wrong with her wiring.

    But either way, you'll definitely get an answer by trying a known good
    phone in the house circuit.

    Good luck
    Chris
     
  4. Jamie

    Jamie Guest

    That sounds more like a phone company service issue.

    the CID service sounds like its not getting properly
    translated from the service to your lines. Your phone
    in effect is picking noise that is screwing up the
    decoding or, the encoding of the CID signal is incorrect
    which should be a phone company issue in both cases.



    http://webpages.charter.net/jamie_5"
     
  5. Ross Herbert

    Ross Herbert Guest

    On Tue, 2 Sep 2008 08:59:41 +0100, "Electronworks.co.uk"

    :what is the audio quality of the phone like?
    :If it is crackly, then water might have got into the phone line (they
    :sometimes use airtight pipes to run the cables inside). This will mess up
    :the caller id signal.
    :

    Not correct...

    The main junction cables between exchanges are usually pressurised (usually dry
    air) to prevent water ingress when minor damage like pin holes in the sheath
    occur and to generate an alarm to bring the attention of the telco to the fact
    that the cable is leaking. Pressurising the cable does NOT have any deleterious
    effect on caller id or any other signals travelling along those cables.

    Usually, if water ingress takes place on a subscriber pair it will produce quite
    loud 50Hz hum (60Hz in the US) and it may even permanently loop the line if bad
    enough. It may also reduce the level and s/n ratio of dtmf signalling.
     
  6. Phil Allison

    Phil Allison Guest

    "Ross Herbert"

    ** Due to all the AC supply frequency current flowing about the soil as a
    result of the MEN system ?


    ** Would the fact this signal arrives during the high voltage ringing cycle
    make matters worse ?



    ...... Phil
     
  7. Joerg

    Joerg Guest

    In the US they often toss power and phone lines into the same trench.
    That's also how it is at this building.
    AFAIK the ID is transmitted between the 1st and 2nd ring, not during the
    ring cycle.
     
  8. Ross Herbert

    Ross Herbert Guest

    On Tue, 02 Sep 2008 08:55:28 -0700, Joerg

    :phil Allison wrote:
    :> "Ross Herbert"
    :>
    :>> The main junction cables between exchanges are usually pressurised
    :>> (usually dry
    :>> air) to prevent water ingress when minor damage like pin holes in the
    :>> sheath
    :>> occur and to generate an alarm to bring the attention of the telco to the
    :>> fact
    :>> that the cable is leaking. Pressurising the cable does NOT have any
    :>> deleterious
    :>> effect on caller id or any other signals travelling along those cables.
    :>>
    :>> Usually, if water ingress takes place on a subscriber pair it will produce
    :>> quite
    :>> loud 50Hz hum (60Hz in the US) and it may even permanently loop the line
    :>> if bad
    :>> enough.
    :>
    :>
    :> ** Due to all the AC supply frequency current flowing about the soil as a
    :> result of the MEN system ?
    :>
    :
    :In the US they often toss power and phone lines into the same trench.
    :That's also how it is at this building.
    :
    :>
    :>> It may also reduce the level and s/n ratio of dtmf signalling.
    :>
    :>
    :> ** Would the fact this signal arrives during the high voltage ringing cycle
    :> make matters worse ?
    :>
    :
    :AFAIK the ID is transmitted between the 1st and 2nd ring, not during the
    :ring cycle.


    Here's the official ACIF (Australia) description - it just says CLI info is
    transmitted "during" the ringing stage, but that could well be between ring
    bursts. The "normal" ring cycle in Australia has a period of 3 sec (0.4 sec ON,
    0.2 sec OFF, 0.4 sec ON, 2 sec OFF), and so on.

    QUOTE
    Transmission of CLI to telephone call recipients (Called Party, B-Party)
    When a call reaches the terminating telephone exchange, that is, the exchange to
    which the called party's line is connected, the exchange normally checks the
    Address Presentation Restriction Indicator.

    If the APRI is set to "presentation restricted" the exchange does not (should
    not) send the calling party's number down the line to the called party.

    If the APRI is set to "presentation allowed", the exchange transmits the calling
    party number during the ringing stage of delivery of the call to the called
    party (if the called party is subscribed to the CLI Presentation service).

    The called party's telephone answering equipment may receive the calling party's
    number in various ways including: in the form of information that is displayed
    on a telephone or computer screen, or automatically recorded in a database, or
    as an audio message, etc.
     
  9. Ross Herbert

    Ross Herbert Guest

    :
    :"Ross Herbert"
    :
    :>
    :> The main junction cables between exchanges are usually pressurised
    :> (usually dry
    :> air) to prevent water ingress when minor damage like pin holes in the
    :> sheath
    :> occur and to generate an alarm to bring the attention of the telco to the
    :> fact
    :> that the cable is leaking. Pressurising the cable does NOT have any
    :> deleterious
    :> effect on caller id or any other signals travelling along those cables.
    :>
    :> Usually, if water ingress takes place on a subscriber pair it will produce
    :> quite
    :> loud 50Hz hum (60Hz in the US) and it may even permanently loop the line
    :> if bad
    :> enough.
    :
    :
    :** Due to all the AC supply frequency current flowing about the soil as a
    :result of the MEN system ?

    That's what I would imagine to be the reason for 50Hz hum. Moisture ingress into
    a cable will effectively connect the cable pairs to earth via a high resistance
    as well as producing a shunt resistance across the pairs.

    :
    :
    :> It may also reduce the level and s/n ratio of dtmf signalling.
    :
    :
    :** Would the fact this signal arrives during the high voltage ringing cycle
    :make matters worse ?
    :

    It sure would. Depending upon the ringer in the destination exchange the ringing
    voltage can exceed 120V pk-pk. This will break down a high shunt resistance due
    to moisture ingress and can even result in ring trip without lifting the B party
    handset.
     
  10. Phil Allison

    Phil Allison Guest

    "Electronworks.co.uk"

    ** Water plus copper wires plus DC voltage

    = recipe for TROUBLE !



    ...... Phil
     
  11. neon

    neon

    1,325
    0
    Oct 21, 2006
    It is a matter of inpedance the air is full of ions during a storm and those CALL ID are not very well protected from incoming static . phone are consideably low inpedance as opposed to caller id.
     
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