Hello.
as header really.
Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

Many thanks
Nick.

Nick wrote:
Hello.
as header really.
Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

Many thanks
Nick.


Of course it can.


The whole exchange kit is backwards compatible to the year dot, except
pre loop disconnect dial stuff won't off-hook get you an operator to ask
to connect you...But you can dial by tapping the off-hook switch..;-)

I cannot remember which wires go where though: there will be two signal
and one bell wire..so if you can identify which plug wires to connect to
in the first place..two will have about 50V DC across them, so that's
one way to find them....the bell wire will give you a nasty tingle when
someone rings you, so conncect theh hamster across various pairs and
dial in from yer mobile. When he leaps, that's teh bell wire..
there are only a finite number of combinations to try, and you won't
screw the exchange up. Not sure about the hamster tho..

Try em till it works..

In article ,
The Natural Philosopher wrote:
I cannot remember which wires go where though: there will be two signal
and one bell wire..so if you can identify which plug wires to connect to
in the first place..two will have about 50V DC across them, so that's
one way to find them....the bell wire will give you a nasty tingle when
someone rings you, so conncect theh hamster across various pairs and
dial in from yer mobile. When he leaps, that's teh bell wire..
there are only a finite number of combinations to try, and you won't
screw the exchange up. Not sure about the hamster tho..

Problem with older phones is the bells are low impedance with effectively
a REN of several and will likely stop any others in the house ringing. But
there are ways round this.

--
*Filthy stinking rich -- well, two out of three ain't bad

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

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
I cannot remember which wires go where though: there will be two signal
and one bell wire..so if you can identify which plug wires to connect to
in the first place..two will have about 50V DC across them, so that's
one way to find them....the bell wire will give you a nasty tingle when
someone rings you, so conncect theh hamster across various pairs and
dial in from yer mobile. When he leaps, that's teh bell wire..
there are only a finite number of combinations to try, and you won't
screw the exchange up. Not sure about the hamster tho..

Problem with older phones is the bells are low impedance with effectively
a REN of several and will likely stop any others in the house ringing. But
there are ways round this.

BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

On Fri, 15 Feb 2008 00:41:08 +0000, The Natural Philosopher
wrote:

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
I cannot remember which wires go where though: there will be two signal
and one bell wire..so if you can identify which plug wires to connect to
in the first place..two will have about 50V DC across them, so that's
one way to find them....the bell wire will give you a nasty tingle when
someone rings you, so conncect theh hamster across various pairs and
dial in from yer mobile. When he leaps, that's teh bell wire..
there are only a finite number of combinations to try, and you won't
screw the exchange up. Not sure about the hamster tho..

Problem with older phones is the bells are low impedance with effectively
a REN of several and will likely stop any others in the house ringing. But
there are ways round this.

BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

Some modern phones use the bell wire, some modern phones don't.
Besides, that is not relevant to the REN. Most modern electronic
phones are high impedance and don't load the phone line with low
impedance bells and electromagnetic earpieces. The ring detection is
done electronically, maybe across the pair, maybe from the ring line,
either way, it has very little effect on the rest of the circuit.


--
Regards, Paul Herber, Sandrila Ltd.
Electronics for Visio http://www.electronics.sandrila.co.uk/

In article ,
The Natural Philosopher wrote:
Problem with older phones is the bells are low impedance with
effectively a REN of several and will likely stop any others in the
house ringing. But there are ways round this.

BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

Some do, some don't.

--
*People want trepanners like they want a hole in the head*

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

In an earlier contribution to this discussion,
The Natural Philosopher wrote:


Problem with older phones is the bells are low impedance with
effectively a REN of several and will likely stop any others in the
house ringing. But there are ways round this.

BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

So? I thought this thread was about *old* telephones - which *do* use the
bell wire when connected to a modular socket - and even when hardwired if
they were not the first in line.

ISTR that old bells had an impediance of 1k ohms - thus having a REN of 4 -
whereas later ones with a REN of 1 had an impedance of 4k ohms. So,
basically, you need to wire a 3k ohm (some say 2.2k - not quite sure why)
resistor in series with the bell, and you're sorted.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In message , Roger Mills
writes
In an earlier contribution to this discussion,
The Natural Philosopher wrote:


Problem with older phones is the bells are low impedance with
effectively a REN of several and will likely stop any others in the
house ringing. But there are ways round this.

BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

So? I thought this thread was about *old* telephones - which *do* use the
bell wire when connected to a modular socket - and even when hardwired if
they were not the first in line.

ISTR that old bells had an impediance of 1k ohms - thus having a REN of 4 -
whereas later ones with a REN of 1 had an impedance of 4k ohms. So,
basically, you need to wire a 3k ohm (some say 2.2k - not quite sure why)

2.2k being a preferred value of a power series perhaps



--
geoff

On Fri, 15 Feb 2008 20:32:51 GMT, wrote:

On 15 Feb,
"Roger Mills" wrote:

ISTR that old bells had an impediance of 1k ohms - thus having a REN of 4 -
whereas later ones with a REN of 1 had an impedance of 4k ohms. So,
basically, you need to wire a 3k ohm (some say 2.2k - not quite sure why)
resistor in series with the bell, and you're sorted.

Some had two coils, which could be wired in series for 4K and parallel for
1K.

The old extension system wired the bells in series and required the coils in
parallel. the newer plug (modern type sockets) have the bells in parallel,
and require the coils in series.

The public network never had the 500 ohm bell coils in parallel in the
phone - they were always wired in series. Very occasionally private
circuits had the coils in parallel.
As you say though, in the old system the bells were connected in
series, up to (officially!) a maximum of four. Or was it six; and four
for a party line?
The early 'plan 4' system of plug and socket telephones was a bit of
fun. There had to be at least one fixed bell (usually a separate
bellset was permanently connected) and each socket had to have a break
jack to maintain continuity of the bell circuit when a phone was
plugged/unplugged.

The concept of REN didn't exist until the new system came about.

--
Frank Erskine

On Thu, 14 Feb 2008 23:45:24 +0000, The Natural Philosopher wrote:

the bell wire will give you a nasty tingle when someone rings you,

True(ish).

so conncect theh hamster across various pairs and dial in from yer
mobile. When he leaps, that's teh bell wire..

Or the incoming pair...

--
Cheers
Dave.

In article et,
"Dave Liquorice" writes:
On Thu, 14 Feb 2008 23:45:24 +0000, The Natural Philosopher wrote:

the bell wire will give you a nasty tingle when someone rings you,

True(ish).

Especially if you are stripping it with your teeth at the time.
Telex lines were even worse (up to 160V peak AC when ringing).

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

On 15 Feb 2008 11:57:51 GMT, Andrew Gabriel wrote:

Especially if you are stripping it with your teeth at the time.

It took me a while to work out why I was getting belts from a BT block I
was attaching lines to for an OB. It was issing with rain, I was soaked
and standing in a puddle. All the lines where controls, 4 wires or musics
ie no volts. I then remembered that we also hada DEL...

I got fed up Telex lines were even worse (up to 160V peak AC when
ringing).

Didn't think telex lines rang as such but the data is +/- 80v from a hi-z
source. I don't think I've been daft enough to come into contact with the
fed to the magnet on my Creed 444 (or any of te other mechanical telex
machines I've had in the past).

--
Cheers
Dave.

On Fri, 15 Feb 2008 20:13:31 +0000 (GMT), "Dave Liquorice"
wrote:

Didn't think telex lines rang as such but the data is +/- 80v from a hi-z
source. I don't think I've been daft enough to come into contact with the
fed to the magnet on my Creed 444 (or any of te other mechanical telex
machines I've had in the past).

It hurts!

I can't feel a normal 50v telephone line voltage, unless there's some
back emf putting nasties on the line. Telephone ringing voltage is a
bit uncomfortable though.

--
Frank Erskine

In article ,
Nick wrote:
Hello. as header really. Phone is an old bakelite gadget with 3 wires
that would have been hardwired into a junction box. Can this be
connected to a more modern plug in BT socket and if so ~ how?

http://web.ukonline.co.uk/freshwater/pstconv1.htm

--
*Learn from your parents' mistakes - use birth control.

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

In article , Nick philremovethisbit
writes

Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

Yes. I'm assuming it's not so old that it doesn't have the BT standard
terminal layout - two rows of screw terminals, 1 to 9 on the top row and
10 to 19 on the bottom row.

Get yourself a BT plug-to-spade-connector lead (aka "a line cord").
Ebay item 170186909828 for example.

Open the phone and remove existing cord.

Remove strap between terminals 4 and 5 and insert a 2.2kohm 1/4W
resistor. This is to reduce the current drawn by the bell - the bells
in old phones are low impedance. You may see "500" on the bell coils -
this is their impedance (500+500). Ensure there is a strap between
terminals 5 and 6 and connect the BLUE wire from the cord to terminal 6.

Ensure there is a strap between terminals 8 and 9 and connect the RED
wire from the cord to terminal 8.

Ensure terminals 16, 17, 18 and 19 are all linked with straps and
connect the WHITE wire from the cord to terminal 18.

Connect the GREEN wire of the cord (it's unused) to terminal 14.

Test.

Be warned that old phones like this may degrade data calls using a modem
or affect a broadband connection.

Be aware that the DC voltage on a phone line is 48V, and that the
ringing current is ~90V AC. Don't work on a phone that's plugged in, as
the ringing voltage can be hair-raising.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(")

On Fri, 15 Feb 2008 08:45:09 +0000, Mike Tomlinson
wrote:

In article , Nick philremovethisbit
writes

Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

Yes. I'm assuming it's not so old that it doesn't have the BT standard
terminal layout - two rows of screw terminals, 1 to 9 on the top row and
10 to 19 on the bottom row.

Not if it's a bakelite one - these have a different terminal layout.
The connections varied depending on the type of phone, ie normal,
shared service or whatever.

Is there a type number printed on the base of the phone, such as 332,
312, or similar?

--
Frank Erskine

After serious thinking Nick wrote :
Hello.
as header really.
Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

I can't remember the old connection colours, but just cut a lead with
plug off a modern but redundant phone. There is a web site dedicated to
the UK phone system which carries lots of information about connecting
old phones to the modern system. Impulse (loop disconnect?) dialing is
still supported by the UK exchanges, so there is no reason for it not
to work.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

yes, same way as a new phone. Getting old cloth wire into an RJ45 is I
assume impossible, so a modern plug with a short stub of wire is
connected to the cloth cord.


Problem with older phones is the bells are low impedance with effectively
a REN of several and will likely stop any others in the house ringing. But
there are ways round this.

This is an often misunderstood issue. REN of most old mechanical bell
phones is 4. Phone exchanges are designed to guarantee all lines will
power a total REN of 4. In practice most will power rather more, as
the wire from the exchange's resistance is usually well below the
limit, hence one old phone plus a couple of modern is not normally a
problem, though it can be occasionally.


BUT EVERYONE ON UK.TELECOM.BRODBAND SWERARS BLIND MODERN PHONES DON'T
USE THE BELL WIRE ANYWAY...

Most have built in caps and don't, but some do. Connection
configurable phones can be connected up pretty much any way, and can
be reconfigured any way. These configurables were designed to be
usable as bugs too, phones were a reliable low cost way to bug people,
and an engineer call to rewire the phone connection didn't arouse
suspicion. So you might one day find a phone so wired, with mic across
the line when on hook.


To the OP: Make sure you connect 2x 1N4001 or similar diodes in
inverse parallel across the receiver (red/green in the handset cord on
most GPO 300/700 series phones) to prevent acoustic shock from loose
connections or dud dial offnormal contacts.. very likely in a phone of
this age, as it can really hurt, and even cause hearing damage.
Originally this would have been a metal rectifier with a lower forward
voltage, but silicon diodes at 0.5-0.6v will still take the edge off
the clicks and pops.

Why do you need diodes when there is already a metal diode stack in
there doing this?


Finally if you dont like dialling the long modern numbers, you can use
a handheld thingy to tone dial. Dials were fine in the days of 3
figure numbers!


NT

On Sat, 16 Feb 2008 14:32:36 -0800 (PST), wrote:

Phone is an old bakelite gadget with 3 wires that would have been hardwired
into a junction box.
Can this be connected to a more modern plug in BT socket and if so ~ how?

yes, same way as a new phone. Getting old cloth wire into an RJ45 is I
assume impossible, so a modern plug with a short stub of wire is
connected to the cloth cord.

The nicest way is to terminate the 'cloth' cord on a bakelite Blocks
Terminal screwed to the wall just as in days of yore, then have a
short 'modern' cord from there to an adjacent NTE socket.

--
Frank Erskine