Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

--
Scott

Where are we going and why am I in this handbasket?

On Mon, 15 Jun 2015 12:52:37 +0100, Scott M
wrote:


Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

If the actors voices are heard from loudspeakers rather than from
their mouths, I can't see why the props need to speak for themselves
;-)



--

Graham.

%Profound_observation%

"Scott M" wrote in message
...
Have promised to lend another local drama group my home brew phone ringer
built from a PIC and a 4 transistor H-bridge driver circuit for a play
this week. I've used this to good effect at my drama group to make various
"proper" (ie bell & gong) phones ring over the years but have just found
it won't run a modern piezo sounder type phone.
I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.
My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.
Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?

My guess is that you need a permanent 50V bias to power the electronics
in the phone so that when you ring it, it is already expecting you.

Also, (But not covered in my beloved, "Atkinson's Telephony", nor
it's predecessot, "Herbert and Proctor") the phone may be expecting
a reversal of the 50V that will presage the forthcoming ringing.

"Scott M" wrote in message ...

Argh!

Have promised to lend another local drama group my home brew phone ringer built from a
PIC and a 4 transistor H-bridge driver circuit for a play this week. I've used this to
good effect at my drama group to make various "proper" (ie bell & gong) phones ring
over the years but have just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to the late 80s)
and nothing happens apart from the LED flashing on the Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output which I'd have
thought enough.

Anyone any suggestions to get it going? I think their phone is a BT Viscount. Am I just
going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

--
Scott

Position a mobile with an appropriately convincing ringtone behind
the prop on the stage. Ring it from the wings with another mobile
stopping when necessary.


michael adams

....

On 15/06/2015 12:52, Scott M wrote:

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.


The BT spec (BT SIN 351) says that ringing voltage is between 40V and
100V a.c. The ringing voltage may be presented with or without a d.c.
voltage bias. Your 40V is right on the minimum limit.

Peter

On 15/06/2015 12:52, Scott M wrote:

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.



Sometimes within a house with wired broadband and the modern phone(s)
will not ring the trick is to use a cheap ADSl filter on every phone (at
the phone end of the wires) to replicate the ringing circuit.

Scroll down to the end of
http://www.adslnation.com/support/filters.php

Note that they state not all cheap filters are correctly wired!


--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

On Monday, 15 June 2015 12:52:40 UTC+1, Scott M wrote:
Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?

Needing a permanent 50V bias to power the electronics is a possibility, at least for the Binatone.

The Viscount should be well-behaved and not require such.

Quite a lot of electronic phones will ring from DC applied to pins 3 and 5 - which can be tested by shorting the master socket capacitor and plugging them into a working phone line. It's easier to generate DC at 50 - 75 volts than a sub-mains frequency AC.

Owain

Viscount? Is that the old sort with the clock that kept dying?
Its interesting as some modern phones work on almost anything while others
do not.

Could it be there is a dc offset on the line?
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Graham." wrote in message
...
On Mon, 15 Jun 2015 12:52:37 +0100, Scott M
wrote:


Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

If the actors voices are heard from loudspeakers rather than from
their mouths, I can't see why the props need to speak for themselves
;-)



--

Graham.

%Profound_observation%

I seem to recall, as I eluded to in my last message, that you needed to have
it superimposed onto a dc vvoltage for modern phones to actually power up
enough to ring as the ring is often now controlled by the logic, not the
ringing signal as such. This allows different rings etc, for different
incoming numbers for those flash harrys who like that sort of thing.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Peter Andrews" wrote in message
...
On 15/06/2015 12:52, Scott M wrote:

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.


The BT spec (BT SIN 351) says that ringing voltage is between 40V and 100V
a.c. The ringing voltage may be presented with or without a d.c. voltage
bias. Your 40V is right on the minimum limit.

Peter

En el artículo , Scott M
escribió:

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

If you're sending the ring current as pure AC with no DC offset, this
can't be fed directly to the piezo sounder as it'd blow it apart. The
phone contains circuitry to detect ring current and convert it into a
low-level signal for the piezo sounder. For this work, the line needs
to have DC on it as well.

Older phones with electromechanical bells feed the ringing voltage
direct to the bell, which is why your ringer works.

--
(\_/)
(='.'=)
(")_(")

On Mon, 15 Jun 2015 13:10:50 +0100, "gareth" wrote:

"Scott M" wrote in message
...
Have promised to lend another local drama group my home brew phone ringer
built from a PIC and a 4 transistor H-bridge driver circuit for a play
this week. I've used this to good effect at my drama group to make various
"proper" (ie bell & gong) phones ring over the years but have just found
it won't run a modern piezo sounder type phone.
I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.
My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.
Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?

My guess is that you need a permanent 50V bias to power the electronics
in the phone so that when you ring it, it is already expecting you.

Also, (But not covered in my beloved, "Atkinson's Telephony", nor
it's predecessot, "Herbert and Proctor") the phone may be expecting
a reversal of the 50V that will presage the forthcoming ringing.

If there is a line reversal from the exchange then it is to prepare the
apparatus for the receipt of calling line identification signaling before the
ring, it is not part of the ring itself. The Viscount, being produced many
years before CLI even appeared on BT's services list to customers doesn't decode
calling line identification and will work with standard ringing as detailed in
SIN 351.

BT SIN 227,242 cover calling line identification, 351 covers line technical
characteristics

http://www.sinet.bt.com/sinet/

In article , michael adams
wrote:

"Scott M" wrote in message
...

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for
a play this week. I've used this to good effect at my drama group to
make various "proper" (ie bell & gong) phones ring over the years but
have just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back
to the late 80s) and nothing happens apart from the LED flashing on
the Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use
that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

-- Scott

Position a mobile with an appropriately convincing ringtone behind the
prop on the stage. Ring it from the wings with another mobile stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

--
Please note new email address:

"charles" wrote in message
...
In article , michael adams
wrote:

"Scott M" wrote in message
...

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for
a play this week. I've used this to good effect at my drama group to
make various "proper" (ie bell & gong) phones ring over the years but
have just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back
to the late 80s) and nothing happens apart from the LED flashing on
the Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use
that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

-- Scott

Position a mobile with an appropriately convincing ringtone behind the
prop on the stage. Ring it from the wings with another mobile stopping
when necessary.


but what happens if somebody else rings that mobile at another time.


It's only switched on prior to the scene in question, and could even
belong to a member of the cast. They could adjust the volume if necessary
before and after each performance. If after all that, it goes off prematurely
someone would need to lift the prop telephone receiver while
surrepticiously switching the mobile off.



michael adams

....

On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.

In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.

--
Cheers
Dave.

On 15/06/2015 19:06, charles wrote:
In , michael adams
wrote:



Position a mobile with an appropriately convincing ringtone behind the
prop on the stage. Ring it from the wings with another mobile stopping
when necessary.


but what happens if somebody else rings that mobile at another time.


The cast do a bit of rapid improvisation!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

In article o.uk,
Dave Liquorice wrote:
On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.

In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.

and if the local service fails?

I once had to make a kettle boil on cue. That was quite an interesting
project.

--
Please note new email address:

Scott M wrote:

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?

Make a recording of a phone ringing, and play it through a loudspeaker?

--
Mike Barnes
Cheshire, England

"Dave Liquorice" wrote in message
ll.co.uk...
On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.


In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.

Delays shouldn't be a problem.

The person in the wings only makes the call when he sees the actor
is approaching the phone. The phone is only allowed to ring x number
of times, after which the actor picks up the receiver.

The fine details could be worked out in rehearsal.


michael adams

....

"Scott M" wrote in message
...

Argh!

Have promised to lend another local drama group my home brew phone ringer
built from a PIC and a 4 transistor H-bridge driver circuit for a play
this week. I've used this to good effect at my drama group to make various
"proper" (ie bell & gong) phones ring over the years but have just found
it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

Anyone any suggestions to get it going? I think their phone is a BT
Viscount. Am I just going to have to find a decent 30+v PSU and use that?


[1] also tested it off a 26v supply I'd been planning to upgrade it to.

Have a look at how voip ATAs do it.

In article ,
michael adams wrote:

"Dave Liquorice" wrote in message
ll.co.uk...
On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.


In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.

Delays shouldn't be a problem.

The person in the wings only makes the call when he sees the actor
is approaching the phone. The phone is only allowed to ring x number
of times, after which the actor picks up the receiver.

The fine details could be worked out in rehearsal.

but the audience appreciate it much more if the actor picks it up mid-ring
and the ring stops.

As long as it doesn't restart when the actor puts the phone back on its
rest.

--
Please note new email address:

In article ,
Scott M writes:

Argh!

Have promised to lend another local drama group my home brew phone
ringer built from a PIC and a 4 transistor H-bridge driver circuit for a
play this week. I've used this to good effect at my drama group to make
various "proper" (ie bell & gong) phones ring over the years but have
just found it won't run a modern piezo sounder type phone.

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

I have a 1980's Binatone. It will only ring with the ring signal
on the bell wire, not if you just apply it across the A and B wires.
I kept it specifically for testing ring wires are working. Most
modern phones only use the A and B wires and won't notice if a
bell wire isn't working.

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

As someone else said, it's right at the bottom of the range.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"charles" wrote in message
...
In article ,
michael adams wrote:

"Dave Liquorice" wrote in message
ll.co.uk...
On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.


but what happens if somebody else rings that mobile at another time.

You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.


In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.

Delays shouldn't be a problem.

The person in the wings only makes the call when he sees the actor
is approaching the phone. The phone is only allowed to ring x number
of times, after which the actor picks up the receiver.

The fine details could be worked out in rehearsal.

but the audience appreciate it much more if the actor picks it up mid-ring
and the ring stops.

That could probably be achieved with plenty of practice and the
use of a stopwatch. Basically the procedure is timed from the
start of the second ring - so the timer isn't caught unawares.
The caller then hangs up after say five seconds to start with.
The number of rings on stage is counted. The duration of the call
is altered until the desired number of rings or half rings are
achieved.
After a while the caller can probably dispense with the timer
with the stopwatch, and do it all in his, or her head.
The person to act as the caller might be finally
selected on that basis - their internal timing ability.



As long as it doesn't restart when the actor puts the phone back on its
rest.


I can't see any reason why it should, if the caller in the wings
has hung up.


michael adams

....

michael adams wrote:
"charles" wrote in message
...
In article ,
michael adams wrote:

"Dave Liquorice" wrote in message
ll.co.uk...
On Mon, 15 Jun 2015 19:06:40 +0100, charles wrote:

Position a mobile with an appropriately convincing ringtone behind
the
prop on the stage. Ring it from the wings with another mobile
stopping
when necessary.

but what happens if somebody else rings that mobile at another time.
You set the mobile that is on set to ring only ring when a particular
number calls it and to immediately reject all other calls.

The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.
In a strong signal area the delay might be fairly short and
consistent but in marginal coverage it can be several seconds
particularly the "call" stage.
Delays shouldn't be a problem.
The person in the wings only makes the call when he sees the actor
is approaching the phone. The phone is only allowed to ring x number
of times, after which the actor picks up the receiver.
The fine details could be worked out in rehearsal.
but the audience appreciate it much more if the actor picks it up mid-ring
and the ring stops.

That could probably be achieved with plenty of practice and the
use of a stopwatch. Basically the procedure is timed from the
start of the second ring - so the timer isn't caught unawares.
The caller then hangs up after say five seconds to start with.
The number of rings on stage is counted. The duration of the call
is altered until the desired number of rings or half rings are
achieved.
After a while the caller can probably dispense with the timer
with the stopwatch, and do it all in his, or her head.
The person to act as the caller might be finally
selected on that basis - their internal timing ability.

If I was up against it, a sound effect is far, far easier to play in
over the PA than try to fiddle about hoping the mobile network wants to
play. Especially as, being village am-dram, signals are ropey at best!

Peversely, being in charge of SFX, the only effect I've run that had
someone comment that it didn't sound real was an actual prop phone
ringing. Argh!

An almost bigger problem is an actor having the right phone. I once went
on stage with a view to making a mobile call in a scene when, with a
ghastly cold sweat that's hard to explain if you've not trodden the
boards, I realised I'd left my prop mobile behind. Thankfully I could
dip into my other jacket pocket and pull out my actual mobile (which I
wasn't ordinarily using as it was one from Nokia's weird-and-wonderful
phase.)

:-)

--
Scott

Where are we going and why am I in this handbasket?

Graham. wrote:

If the actors voices are heard from loudspeakers rather than from
their mouths, I can't see why the props need to speak for themselves
;-)

Don't start me on mic'd sound in a village hall. Trying to explain to
people that by the time they're speaking up enough for the mics to pick
them up properly that they're hitting the back wall anyway is tiresome!

--
Scott

Where are we going and why am I in this handbasket?

On Mon, 15 Jun 2015 20:32:46 +0100, charles
wrote:



and if the local service fails?

I once had to make a kettle boil on cue. That was quite an interesting
project.

If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.
As mobiles are being discussed then you could record a custom ring
tone featuring the whistle and hide the phone near the kettle .

G.Harman

Peter Andrews wrote:
On 15/06/2015 12:52, Scott M wrote:

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

The BT spec (BT SIN 351) says that ringing voltage is between 40V and
100V a.c. The ringing voltage may be presented with or without a d.c.
voltage bias. Your 40V is right on the minimum limit.

And we have a winner :-)

After much swearing, fiddling, cursing, googling, shouting and getting
nowhere as I had no way of increasing the PSU voltage I had a bit of a
brainwave.

The other week I finally got around to opening up a home brew BS1363
socket-in-a-box that came my way about 25 years ago as I wanted a home
for a general purpose motor speed controller. It looked like it had been
built as a bit of home brew test gear and inside was a mystery
transformer that I'd always assumed was an isolating type although, on
closer inspection, only had 3 wires. This was slung in the trailer for
going to the tip and the controller installed.

Then, after reading Peter's post, I got to wondering if it wasn't a step
up/down job. I rung it out and reckoned it was a 1:2 job, although the
way it had been wired implied it was giving 120v on the box socket.

Fished the transformer back out of the trailer, attached it to the
output of the H-bridge, et voila, ~80v P-P on the scope. With fingers a
tremble I attached it to the 2-wire phone and, as Leslie Phillips would
say, ding dong :-)

So, thank you Peter for prodding me in the right direction. I knew that
I was a bit on the low side but assumed that a
rectify-and-power-a-sounder ringer would just be a bit on the quiet side
rather than silent

--
Scott

Where are we going and why am I in this handbasket?

Andrew Gabriel wrote:
In article ,
Scott M writes:

I've got two phones, one two wire and one three (Binatone dating back to
the late 80s) and nothing happens apart from the LED flashing on the
Binatone.

I have a 1980's Binatone. It will only ring with the ring signal
on the bell wire, not if you just apply it across the A and B wires.
I kept it specifically for testing ring wires are working. Most
modern phones only use the A and B wires and won't notice if a
bell wire isn't working.

Yes, I expected that and the Binatone was using 5 & 3 to get LED
flashes. I'm going to build in a CO switch to switch between pins 2 & 3
as I've got all flashy and mounted a BT socket on the new case (it was
the PSU upgrade that got me realising that it wasn't going to run new(!)
phones.)


My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

As someone else said, it's right at the bottom of the range.

See my reply to Peter, got it sorted in the end - though I was still
trying to build the damn thing into its new box during rehearsals!!

--
Scott

Where are we going and why am I in this handbasket?

gareth wrote:

My guess is that you need a permanent 50V bias to power the electronics
in the phone so that when you ring it, it is already expecting you.

I attempted to feed the 30v into the 3-wire at the same time as sending
a rining signal and nowt happened. But see elsewhere, got it going :-)

--
Scott

Where are we going and why am I in this handbasket?

In article ,
wrote:
On Mon, 15 Jun 2015 20:32:46 +0100, charles
wrote:



and if the local service fails?

I once had to make a kettle boil on cue. That was quite an interesting
project.

If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

no - you had to see it steaming - I didn't write the play

As mobiles are being discussed then you could record a custom ring
tone featuring the whistle and hide the phone near the kettle .

G.Harman

and when we did this it was long before the days of mobile phones

In article o.uk,
Dave Liquorice wrote:
The biggest snag will be the variable delay between pressing "call"
and the on set phone ringing and pressing "hang up" and the onset
phone stopping.

Yes. When digital mobiles were just becoming common, many TV dramas wanted
to show them actually working - lighting up and displaying the name etc.
Experience showed never to do this all on one shot (ie live action) as the
time it took to ring was extremely variable. So near always done as a
cutaway shot.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

But you'd see the steam on stage? Dry ice is the answer. ;-)

--
*IF A PARSLEY FARMER IS SUED, CAN THEY GARNISH HIS WAGES?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

But you'd see the steam on stage? Dry ice is the answer. ;-)


having that coming out of a kettle spout on cue?

anyhow, it's nasty stuff.

In article ,
Charles Hope wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

But you'd see the steam on stage? Dry ice is the answer. ;-)


having that coming out of a kettle spout on cue?

anyhow, it's nasty stuff.

and I forgot to say "what do you then pour into the teapot?"

In article ,
Charles Hope wrote:
In article ,
Charles Hope wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

But you'd see the steam on stage? Dry ice is the answer. ;-)


having that coming out of a kettle spout on cue?

anyhow, it's nasty stuff.

and I forgot to say "what do you then pour into the teapot?"

Oh indeed. However, I'd have thought the time a kettle takes to boil a
given quantity of water from a given starting temperature would be pretty
consistent? But maybe too long for the scene. ;-)

--
*If I throw a stick, will you leave?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave Plowman (News) wrote:
In article ,
Charles Hope wrote:
In article ,
Charles Hope wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

But you'd see the steam on stage? Dry ice is the answer. ;-)


having that coming out of a kettle spout on cue?

anyhow, it's nasty stuff.

and I forgot to say "what do you then pour into the teapot?"

Oh indeed. However, I'd have thought the time a kettle takes to boil a
given quantity of water from a given starting temperature would be pretty
consistent? But maybe too long for the scene. ;-)

That was part of the problem, the other was that actors are not automatons
- their delivery varies from night to night.

On 16/06/2015 09:36, Charles Hope wrote:
In article ,
wrote:
On Mon, 15 Jun 2015 20:32:46 +0100, charles
wrote:



and if the local service fails?

I once had to make a kettle boil on cue. That was quite an interesting
project.

If the time period of the play was right you could just activate a
whistle sound on a whistling one, the audience need not know it isn't
hot.

no - you had to see it steaming - I didn't write the play

Put a block of metal with a thermostatic heater set to 120C.
Put a balloon with some water in it above it and pierce it with a
solenoid at the Q. It will boil immediately.

On Tue, 16 Jun 2015 11:52:55 +0100, Charles Hope
wrote:

That was part of the problem, the other was that actors are not automatons
- their delivery varies from night to night.

So what worked?

Little bit of water, lot of power?

Water boiling offstage ahead of time, steam cunningly piped to kettle?


Thomas Prufer

On Tue, 16 Jun 2015 08:06:08 +0100, Scott M
wrote:

Peter Andrews wrote:
On 15/06/2015 12:52, Scott M wrote:

My circuit runs off 20v[1] and chucks out about 40v P-P on the output
which I'd have thought enough.

The BT spec (BT SIN 351) says that ringing voltage is between 40V and
100V a.c. The ringing voltage may be presented with or without a d.c.
voltage bias. Your 40V is right on the minimum limit.

And we have a winner :-)

After much swearing, fiddling, cursing, googling, shouting and getting
nowhere as I had no way of increasing the PSU voltage I had a bit of a
brainwave.

The other week I finally got around to opening up a home brew BS1363
socket-in-a-box that came my way about 25 years ago as I wanted a home
for a general purpose motor speed controller. It looked like it had been
built as a bit of home brew test gear and inside was a mystery
transformer that I'd always assumed was an isolating type although, on
closer inspection, only had 3 wires. This was slung in the trailer for
going to the tip and the controller installed.

Then, after reading Peter's post, I got to wondering if it wasn't a step
up/down job. I rung it out and reckoned it was a 1:2 job, although the
way it had been wired implied it was giving 120v on the box socket.

Fished the transformer back out of the trailer, attached it to the
output of the H-bridge, et voila, ~80v P-P on the scope. With fingers a
tremble I attached it to the 2-wire phone and, as Leslie Phillips would
say, ding dong :-)

So, thank you Peter for prodding me in the right direction. I knew that
I was a bit on the low side but assumed that a
rectify-and-power-a-sounder ringer would just be a bit on the quiet side
rather than silent

Yes your 40Vp-p was only about 14V rms (if it was a sinewave) which is
normally what is meant by "ac". So 40V ac minimum would be 2.8 times
this p-p, i.e. 112v p-p.
--
Dave W

Dave W wrote:
On Tue, 16 Jun 2015 08:06:08 +0100, Scott M

So, thank you Peter for prodding me in the right direction. I knew that
I was a bit on the low side but assumed that a
rectify-and-power-a-sounder ringer would just be a bit on the quiet side
rather than silent

Yes your 40Vp-p was only about 14V rms (if it was a sinewave) which is
normally what is meant by "ac". So 40V ac minimum would be 2.8 times
this p-p, i.e. 112v p-p.

Sinewave? Sinewave!?! We'll have none of those poncy things round 'ere! :-)

It's a fairly ragged square wave and I'd not thought about RMS values.
The web pages covering ringer specs are a bit vague so I'd not thought
about what they were really saying. It's of 50% duty cycle so similar
values to your calcs tho.

--
Scott

Where are we going and why am I in this handbasket?

On 17/06/15 11:49, Scott M wrote:
Dave W wrote:
On Tue, 16 Jun 2015 08:06:08 +0100, Scott M

So, thank you Peter for prodding me in the right direction. I knew
that I was a bit on the low side but assumed that a
rectify-and-power-a-sounder ringer would just be a bit on the quiet
side rather than silent

Yes your 40Vp-p was only about 14V rms (if it was a sinewave) which is
normally what is meant by "ac". So 40V ac minimum would be 2.8 times
this p-p, i.e. 112v p-p.

Sinewave? Sinewave!?! We'll have none of those poncy things round 'ere! :-)

It's a fairly ragged square wave and I'd not thought about RMS values.
The web pages covering ringer specs are a bit vague so I'd not thought
about what they were really saying. It's of 50% duty cycle so similar
values to your calcs tho.

yerrs. Had this issue years ago with some PABX's that couldn't ring some
analogue phones.


Simple lack of voltage.

Oddly enough you can use some audio transformers designed for very old
audio amps from, way back that are still available as spares to pep up
the output a bit. Or a small '100V line' transformer.




--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.