GPO Telephone 332 Bell Issues

Discussion in 'UK VOIP' started by E27002, Sep 30, 2009.

  1. E27002

    E27002 Guest

    Can anyone advise on this issue and how to fix it?

    I have in my possession a GPO Telephone 332. In 2001 I used it in
    Edinburgh plugged into a standard BT master socket. AFAIR it worked
    just fine.

    The 'phone is converted, i.e. it has a 3.3k resistor in series with
    its bell. Just recently I tried to utilize at my home here in the US
    on my VoIP setup.

    My internet acess is thru my Cable company. The Cable interface box
    is connected to a D-Link router. It in turn is connected to a UK
    Standard Linksys/ATA router. The first RJ11 output port on the
    Linksys is connected to one pair of a Cat5e cable that runs to my
    Study. The run is eighty feet max.

    The Cat5e pair is terminated thru a wall in my study with a standard
    BT master outlet. When I plug my GPO 332 into said master outlet, I
    have dial tone. Clearly I cannot make calls. However, receiving them
    is also an issue. The bell in the 332 barely rings. The bell just
    "tinkles" a little.

    Is this because the ATA does not provide enough "juice"? Could the
    bell have deteriorated during its eight years of disuse?

    Thanks
     
    E27002, Sep 30, 2009
    #1
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  2. E27002

    Graham. Guest

    "E27002" <> wrote in message
    news:...
    > Can anyone advise on this issue and how to fix it?
    >
    > I have in my possession a GPO Telephone 332. In 2001 I used it in
    > Edinburgh plugged into a standard BT master socket. AFAIR it worked
    > just fine.
    >
    > The 'phone is converted, i.e. it has a 3.3k resistor in series with
    > its bell. Just recently I tried to utilize at my home here in the US
    > on my VoIP setup.
    >
    > My internet acess is thru my Cable company. The Cable interface box
    > is connected to a D-Link router. It in turn is connected to a UK
    > Standard Linksys/ATA router. The first RJ11 output port on the
    > Linksys is connected to one pair of a Cat5e cable that runs to my
    > Study. The run is eighty feet max.
    >
    > The Cat5e pair is terminated thru a wall in my study with a standard
    > BT master outlet. When I plug my GPO 332 into said master outlet, I
    > have dial tone. Clearly I cannot make calls. However, receiving them
    > is also an issue. The bell in the 332 barely rings. The bell just
    > "tinkles" a little.
    >
    > Is this because the ATA does not provide enough "juice"? Could the
    > bell have deteriorated during its eight years of disuse?
    >
    > Thanks


    My experience is an ATA does not provide nearly as much ringing
    current as my BT line.
    Try reducing the value of the 3k3 resistor, try shorting it out completely.
    The reason it is there in the first place is to raise the impedance of the
    bell so that parallel modern HI-Z ringers get a fair share of the available
    current. As this is likely to be the only phone on the ATA port that won't
    be an issue.

    --
    Graham.

    %Profound_observation%
     
    Graham., Sep 30, 2009
    #2
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  3. E27002

    Dave Higton Guest

    In message <>
    E27002 <> wrote:

    > Can anyone advise on this issue and how to fix it?
    >
    > I have in my possession a GPO Telephone 332. In 2001 I used it in
    > Edinburgh plugged into a standard BT master socket. AFAIR it worked
    > just fine.
    >
    > The 'phone is converted, i.e. it has a 3.3k resistor in series with
    > its bell. Just recently I tried to utilize at my home here in the US
    > on my VoIP setup.
    >
    > My internet acess is thru my Cable company. The Cable interface box
    > is connected to a D-Link router. It in turn is connected to a UK
    > Standard Linksys/ATA router. The first RJ11 output port on the
    > Linksys is connected to one pair of a Cat5e cable that runs to my
    > Study. The run is eighty feet max.
    >
    > The Cat5e pair is terminated thru a wall in my study with a standard
    > BT master outlet. When I plug my GPO 332 into said master outlet, I
    > have dial tone. Clearly I cannot make calls. However, receiving them
    > is also an issue. The bell in the 332 barely rings. The bell just
    > "tinkles" a little.
    >
    > Is this because the ATA does not provide enough "juice"? Could the
    > bell have deteriorated during its eight years of disuse?


    With a 3k3 resistor in series with the bell, I'm astonished it
    rings at all.

    Dave
     
    Dave Higton, Oct 1, 2009
    #3
  4. E27002

    Owain Guest

    On 1 Oct, 21:47, Dave Higton wrote:
    > With a 3k3 resistor in series with the bell, I'm astonished it
    > rings at all.


    Original in the old Plan Whatever arrangement there could be up to 6
    phones with series connected bells, so any phone could have up to 5k
    (5 bells x 2 solenoids x 500R per solenoid) in series with its bell.

    I suppose it's also possible that the conversion retained the original
    bell capacitor, which is now faulty.

    Owain
     
    Owain, Oct 1, 2009
    #4
  5. E27002

    John Weston Guest

    In article <>, ""Russell
    W. Barnes"" wrote:
    >


    >
    > The point I am making is this: Were telephones fitted with a bell designed
    > to resonate (or near-resonate) at the ringing frequency, or is this just
    > co-incidental?
    >
    > And:
    >
    > Might a capacitor included in the OPs bell cct improve matters by wringing
    > (no pun intended) as much out of the bell current as possible?


    You are probably right, since the bistable ringers (two coils, with the
    long ringer hammer going down between them to the gongs) worked best at
    the original 16 2/3Hz and sounded terrible on 25Hz. I remember falling
    back on the traditional motor generator ringers rather than try to do it
    with the electronics of the day. Half-wave rectified 50Hz was useless on
    most installations.

    --
    John W
    I you want to mail me, replace the obvious with co.uk twice
     
    John Weston, Oct 5, 2009
    #5
  6. E27002

    russell_w_b Guest

    On 5 Oct, 12:58, John Weston <> wrote:
    > In article <>, ""Russell
    >
    > W. Barnes"" wrote:
    >
    > > The point I am making is this:  Were telephones fitted with a bell designed
    > > to resonate (or near-resonate) at the ringing frequency, or is this just
    > > co-incidental?

    >
    > > And:

    >
    > > Might a capacitor included in the OPs bell cct improve matters by wringing
    > > (no pun intended) as much out of the bell current as possible?

    >
    > You are probably right, since the bistable ringers (two coils, with the
    > long ringer hammer going down between them to the gongs) worked best at
    > the original 16 2/3Hz and sounded terrible on 25Hz.  


    John,

    Thanks for the reply. I have just tested a Magneto Generator No:26A
    (ex-Type 'F' field-telephone) and found it delevers a little more
    'whoomph' than the Linesman's Telephone 704 I was using (batteries not
    up to scratch?). I can get 60mA into a 1200 Ohm resistor, and
    vigorous turning gives an O/C voltage of 90V and a S/C current of
    100mA, so I'm guessing its impedance was designed to match - more-or-
    less - a 1000R bell-motor; maximum power-transfer, and all that... I
    shall undertake further tests.

    Trouble is, I'll need a steady rotation to keep a stable 16 2/3 Hz! I
    also have one of those REN extenders which I shall look at with a view
    to providing an experimental ring-current source (probably 25Hz,
    though).

    When, and why, was sub-cycle 1/3 mains-frequency replaced with 1/2
    mains-frequency for ringing, and were bell-motors produced after this
    date re-designed for the higher frequency?
    --

    Regds,

    Russell W. B.
    http://www.huttonrow.co.uk
    http://www.flickr.com/photos/russell_w_b
     
    russell_w_b, Oct 5, 2009
    #6
  7. E27002

    John Weston Guest

    In article <0aeb1288-1053-4f86-8040-ecf60c0aa978
    @e18g2000vbe.googlegroups.com>, "russell_w_b" wrote:

    > When, and why, was sub-cycle 1/3 mains-frequency replaced with 1/2
    > mains-frequency for ringing, and were bell-motors produced after this
    > date re-designed for the higher frequency?


    The ring and tone generator was 3-phase, providing 3-phase ringing
    cadence as well, via cam-driven contacts (400ms on, 200ms off, 400ms on
    2s off with the next "phase" starting after the last 400ms on and then
    once more before restarting the cycle) The 16 2/3Hz ring current
    frequency is a third of 50Hz, but I don't know if this is of any
    significance...

    I don't know exactly when it went to 25Hz, probably when it eventually
    was electronically generated? I see 16 2/3 was a common frequency used
    on early railways, so it could have come from there. I could look it up
    in Atkinson, but that's likely to give the how rather than the why.

    --
    John W
    I you want to mail me, replace the obvious with co.uk twice
     
    John Weston, Oct 5, 2009
    #7
  8. E27002

    russell_w_b Guest

    On 5 Oct, 14:44, John Weston <> wrote:

    8><--------------------------
    > I could look it up
    > in Atkinson, but that's likely to give the how rather than the why.
    >


    I shall look in my 'Atkinson' when I get home. It was written in
    1947, and I have a feeling it still refers to 16 2/3 Hz. Poole's
    'Telephone Handbook' refers to 16 2/3 Hz, and it is slightly older
    than 'Atkinson'.

    Interestingly, I can find no reference (in Atkinson) to resonance in
    bell circuits, although a good explananation of polarised ringing is
    given.
    --

    Regds,

    Russell W. B.
    http://www.huttonrow.co.uk
    http://www.flickr.com/photos/russell_w_b
     
    russell_w_b, Oct 5, 2009
    #8
  9. E27002

    Gaius Guest

    John Weston wrote:
    > In article <0aeb1288-1053-4f86-8040-ecf60c0aa978
    > @e18g2000vbe.googlegroups.com>, "russell_w_b" wrote:
    >
    >> When, and why, was sub-cycle 1/3 mains-frequency replaced with 1/2
    >> mains-frequency for ringing, and were bell-motors produced after this
    >> date re-designed for the higher frequency?

    >
    > The ring and tone generator was 3-phase, providing 3-phase ringing
    > cadence as well, via cam-driven contacts (400ms on, 200ms off, 400ms on
    > 2s off with the next "phase" starting after the last 400ms on and then
    > once more before restarting the cycle) The 16 2/3Hz ring current
    > frequency is a third of 50Hz, but I don't know if this is of any
    > significance...
    >
    > I don't know exactly when it went to 25Hz, probably when it eventually
    > was electronically generated? I see 16 2/3 was a common frequency used
    > on early railways, so it could have come from there. I could look it up
    > in Atkinson, but that's likely to give the how rather than the why.
    >


    As I remember, this came about when the "New" PMBXs like the 3+12 came
    in (plastic rather than wooden cases!). The ring current was obtained
    from a power unit which had a cheap, simple 1/2 frequency divider
    working off the mains. 16 2/3Hz was too difficult to derive, for what
    was a low-cost installation.

    I've no idea when/why 25Hz became the PSTN primary standard, though.
     
    Gaius, Oct 5, 2009
    #9
  10. E27002

    Bodincus Guest

    Gaius:
    > John Weston wrote:
    >> In article <0aeb1288-1053-4f86-8040-ecf60c0aa978
    >> @e18g2000vbe.googlegroups.com>, "russell_w_b" wrote:
    >>
    >>> When, and why, was sub-cycle 1/3 mains-frequency replaced with 1/2
    >>> mains-frequency for ringing, and were bell-motors produced after this
    >>> date re-designed for the higher frequency?

    >>
    >> The ring and tone generator was 3-phase, providing 3-phase ringing
    >> cadence as well, via cam-driven contacts (400ms on, 200ms off, 400ms
    >> on 2s off with the next "phase" starting after the last 400ms on and
    >> then once more before restarting the cycle) The 16 2/3Hz ring current
    >> frequency is a third of 50Hz, but I don't know if this is of any
    >> significance...
    >>
    >> I don't know exactly when it went to 25Hz, probably when it eventually
    >> was electronically generated? I see 16 2/3 was a common frequency
    >> used on early railways, so it could have come from there. I could
    >> look it up in Atkinson, but that's likely to give the how rather than
    >> the why.
    >>

    >
    > As I remember, this came about when the "New" PMBXs like the 3+12 came
    > in (plastic rather than wooden cases!). The ring current was obtained
    > from a power unit which had a cheap, simple 1/2 frequency divider
    > working off the mains. 16 2/3Hz was too difficult to derive, for what
    > was a low-cost installation.
    >
    > I've no idea when/why 25Hz became the PSTN primary standard, though.

    Because dividing a frequency in half requires only some cheap, durable
    and reliable electronics (diodes) but dividing a frequency by three
    requires expensive and subject to wear an tear electromechanical devices?
    BTW, while interesting for us geeks, can you please remove
    uk.telecom.voip from your discussion?
    Thanks

    X-Post and FUs set
    --
    Bodincus - The Y2K Druid
    ----------------------------
    Law 42 on computing: Anything that could go wron%½ $
    $: Access Violation - Core dumped
     
    Bodincus, Oct 6, 2009
    #10
  11. E27002

    E27002 Guest

    On Oct 6, 4:48 am, Bodincus <> wrote:
    > Gaius:
    >
    >
    >
    > > John Weston wrote:
    > >> In article <0aeb1288-1053-4f86-8040-ecf60c0aa978
    > >> @e18g2000vbe.googlegroups.com>, "russell_w_b" wrote:

    >
    > >>> When, and why, was sub-cycle 1/3 mains-frequency replaced with 1/2
    > >>> mains-frequency for ringing, and were bell-motors produced after this
    > >>> date re-designed for the higher frequency?

    >
    > >> The ring and tone generator was 3-phase, providing 3-phase ringing
    > >> cadence as well, via cam-driven contacts (400ms on, 200ms off, 400ms
    > >> on 2s off with the next "phase" starting after the last 400ms on and
    > >> then once more before restarting the cycle) The 16 2/3Hz ring current
    > >> frequency is a third of 50Hz, but I don't know if this is of any
    > >> significance...

    >
    > >> I don't know exactly when it went to 25Hz, probably when it eventually
    > >> was electronically generated?  I see 16 2/3 was a common frequency
    > >> used on early railways, so it could have come from there.  I could
    > >> look it up in Atkinson, but that's likely to give the how rather than
    > >> the why.

    >
    > > As I remember, this came about when the "New" PMBXs like the 3+12 came
    > > in (plastic rather than wooden cases!). The ring current was obtained
    > > from a power unit which had a cheap, simple 1/2 frequency divider
    > > working off the mains. 16 2/3Hz was too difficult to derive, for what
    > > was a low-cost installation.

    >
    > > I've no idea when/why 25Hz became the PSTN primary standard, though.

    >
    > Because dividing a frequency in half requires only some cheap, durable
    > and reliable electronics (diodes) but dividing a frequency by three
    > requires expensive and subject to wear an tear electromechanical devices?
    > BTW, while interesting for us geeks, can you please remove
    > uk.telecom.voip from your discussion?
    > Thanks
    >

    Point taken! However, with regards to my original query, VoIP is
    relevant. If my ATA is not providing current at the right frequency,
    that may be part of the issue with the bell in my telephone. I am
    going to check if the capacitor is still in the circuit. But, based
    on the forgoing, trying to use a 332 with an ATA may not be smart.
    Perhaps a 200 series ‘phone with a separate electronic audible device
    is a better solution
     
    E27002, Oct 7, 2009
    #11
  12. E27002

    Owain Guest

    On 7 Oct, 21:35, "Russell W. Barnes" wrote:
    > Could you obtain an 8700 series telephone (they sometimes pop up on eBay),
    > one of the last dial-types, like a BT 'Yeoman'  (the brown, later variant of
    > the 746)?  They have a 4k ringer rather than a 1k one.  AFAIK the mounting
    > screw-holes on the bell magnet yoke are the same, but if not, replacing the
    > 2 x 500R bobbins of your 332 with the 2 x 2k bobbins is simple enough.


    Or you can buy 4000k ringers easily enough - these didn't sell but as
    the seller is a trader they'll probably get readvertised
    http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250494917874

    I would also suggest basic fault-finding, checking the capacitor if in
    circuit, checking the coils or 3.3k resistor are what they are
    supposed to be, and adjusting the gongs

    Owain
     
    Owain, Oct 7, 2009
    #12
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