duplicating phone and ring voltage

[mm]

I need to connect some telephone-type things together in my own little
circuit, and test them, but I don't know a simple method or what
voltages to use. I think I need to use some wire, some kind of DC
power, something to put a ring-signal on the line, a phone, and
whatever I am testing.

For example, I'm getting a replacement for my all-time favorite phone
answering machine, but the owner has forgotten the 3-digit code for
remote message retrieval. I'm willing to try all 900 or 1000,
probably while I'm watching tv, but only if I can get it to go
quickly. So I need a test line to ring it directly, have the machine
answer, and punch in the code.

Also I have 2 fax machines, one that sends and one that receives!
I'm pretty sure I can get it down to one that does both.

I don't have two phone lines, and even if I did, I think things would
run quicker with my own little circuit.

In the 7th grade, we had two candlestick phones and a dry cell to play
with during ham radio club, and everything worked (except it didn't
ring, but that was ok because they had no bells. )

Any help appreciated.

 

[JANA]

Phones need 48 Volts DC with an in series of 600 to 800 ohm source. The ring
is 96 Volts at 25 Hz.

For the answering machine, if it is a name brand, you should be able to get
the information about how to reset the remote code. If it is a fixed
uninique code, then you have a problem. For what it is worth, maybe it would
be better to simply get a new answering machine.

--

JANA
_____


I need to connect some telephone-type things together in my own little
circuit, and test them, but I don't know a simple method or what
voltages to use. I think I need to use some wire, some kind of DC
power, something to put a ring-signal on the line, a phone, and
whatever I am testing.

For example, I'm getting a replacement for my all-time favorite phone
answering machine, but the owner has forgotten the 3-digit code for
remote message retrieval. I'm willing to try all 900 or 1000,
probably while I'm watching tv, but only if I can get it to go
quickly. So I need a test line to ring it directly, have the machine
answer, and punch in the code.

Also I have 2 fax machines, one that sends and one that receives!
I'm pretty sure I can get it down to one that does both.

I don't have two phone lines, and even if I did, I think things would
run quicker with my own little circuit.

In the 7th grade, we had two candlestick phones and a dry cell to play
with during ham radio club, and everything worked (except it didn't
ring, but that was ok because they had no bells. )

Any help appreciated.

 

[Kevin Ricks]

I need to connect some telephone-type things together in my own little
circuit, and test them, but I don't know a simple method or what
voltages to use. I think I need to use some wire, some kind of DC
power, something to put a ring-signal on the line, a phone, and
whatever I am testing.

For example, I'm getting a replacement for my all-time favorite phone
answering machine, but the owner has forgotten the 3-digit code for
remote message retrieval. I'm willing to try all 900 or 1000,
probably while I'm watching tv, but only if I can get it to go
quickly.

Are you sure you can't just program a new access code without knowing the
old one? My machine does not ask for any codes at the base unit for
anything. The new code just replaces the old. Only remote access requires
the code. But yours may be different.

Kevin

 

[[email protected]]

there are little circuit boxes that immitate the phone line, last I saw
one about 60 bucks

 

[Michael Kennedy]

there are little circuit boxes that immitate the phone line, last I saw

one about 60 bucks

Thats the way to go... Getting the operating voltage (48vdc) isn't that
hard just hook up 4 12 volt batteries in series with an 800 ohm (If I
remember correctly) reisistor on the end. Getting a 20hz ringtone is the
difficult part since the wall current is 60hz.. I never figured out an easy
way to make my phones ring.

- Mike

 

[Tony Hwang]

I need to connect some telephone-type things together in my own little
circuit, and test them, but I don't know a simple method or what
voltages to use. I think I need to use some wire, some kind of DC
power, something to put a ring-signal on the line, a phone, and
whatever I am testing.

For example, I'm getting a replacement for my all-time favorite phone
answering machine, but the owner has forgotten the 3-digit code for
remote message retrieval. I'm willing to try all 900 or 1000,
probably while I'm watching tv, but only if I can get it to go
quickly. So I need a test line to ring it directly, have the machine
answer, and punch in the code.

Also I have 2 fax machines, one that sends and one that receives!
I'm pretty sure I can get it down to one that does both.

I don't have two phone lines, and even if I did, I think things would
run quicker with my own little circuit.

In the 7th grade, we had two candlestick phones and a dry cell to play
with during ham radio club, and everything worked (except it didn't
ring, but that was ok because they had no bells. )

Any help appreciated.

Hmmm,
In this digital age, playing with analog?

 

[Dave D]

Thats the way to go... Getting the operating voltage (48vdc) isn't that
hard just hook up 4 12 volt batteries in series with an 800 ohm (If I
remember correctly) reisistor on the end. Getting a 20hz ringtone is the
difficult part since the wall current is 60hz.. I never figured out an
easy way to make my phones ring.

- Mike

There's several easy ways to generate a 25Hz at 96v, one is an old
fashioned multivibrator driving a 120V/12V transformer secondary, (ie a 25Hz
inverter) and adjusting the multivibrator's supply down to get 96V. It's
rough and ready but there's no reason why it shouldn't work, and it uses a
few standard, off the shelf components.

Dave

 

[Jay]

snip

I'm willing to try all 900 or 1000, > probably while I'm watching tv, but
only if I can get it to go quickly. So I need a test line to ring it
directly, >have the machine answer, and punch in the code.

snip

Jana:

Seems like a lot of effort for short money (bad ROI)?

What Make and Model is this unit?

I bet we could find you one on e-Bay that doesn't entail hooking up multiple
12 volt batteries in series and punching in a possible 1,000 codes to get it
to work!

Do you really want to sit amongst multiple car batteries in your living room
watching TV punching in codes all night and then recharging them, trying
1,000 possible codes is going to take some time and will probably require
one, or more, recharges.

Just my $.02 worth. Voicemail!!!!

Jay

 

[Beachcomber]

Hmmm,
In this digital age, playing with analog?

Yup... It's called POTS Plain Old Telephone Service.

One thing to consider... Many fax machines and other devices have
dial tone detection circuits. The mere presence of DC voltage on the
line will not make them dial. Also, getting the correct 20 Hz ring
frequency and voltage (with the right current) in a home grown circuit
is a pain unless you are willing to get fairly elaborate.

Here is a fancy Ringdown Circuit from Viking Electronics. List price
is $106

http://www.vikingelectronics.com/products/pdf/dle-200b(sm).pdf

Beachcomber

 

[[email protected]]

Black magic ring generator-

http://www.camblab.com/home.htm

Dave

 

[Dave Plowman (News)]

Phones need 48 Volts DC with an in series of 600 to 800 ohm source. The
ring is 96 Volts at 25 Hz.

That's the spec to allow for vast voltage drop over the miles of cable
between phones. Just to get two to talk to one another 9 volts will work
just ok. Indeed if you're talking about old non electronics phones with
carbon mics 1.5 volts will be ok for short runs.

 

[Ken Layton]

Try the Viking Electronics model DLE200 telephone line simulator box.
It's only about 5" by 2 " with phone jacks on it. It only cost around
$100 about 12 years ago.

 

[mm]

Phones need 48 Volts DC with an in series of 600 to 800 ohm source. The ring
is 96 Volts at 25 Hz.

Thanks a lot.

For the answering machine, if it is a name brand, you should be able to get
the information about how to reset the remote code. If it is a fixed
uninique code, then you have a problem.

It is a fixed code. A friend of mine and I each bought one 21 years
ago, and the code was printed on the box, not on the bottom of the
unit that became more common. I wish it had been on the bottom; we
would still have it! This new one is from the wife of a friend, and
she stopped using it a couple years ago and has forgotten the code.

It's Code-a-Phone, model 2530 or similar model.

For what it is worth, maybe it would
be better to simply get a new answering machine.

Like I say, this is my all-time favorite phone machine. I have about
10 others, all different brands or models, that I've bought in the
last 2 or 3 years, paying 1 to 3 dollars each at hamfests. They all
work as designed but I don't like how they work.

 

[Bill Janssen]

That's the spec to allow for vast voltage drop over the miles of cable
between phones. Just to get two to talk to one another 9 volts will work
just ok. Indeed if you're talking about old non electronics phones with
carbon mics 1.5 volts will be ok for short runs.

I have always used the assumptions that there was 400 Ohms in the
telephone. The telephone wants
20 milli-Amps or more so that says you need 8 Volts or more (per phone)
The 48 Volts (really 52)
that the central office uses is to push at least 20 milli-Amps through
the longest line.

Bill K7NOM

 

[[email protected]]

I used to have a hand cranked generator from an old phone. This puts out
exactly what you need. Think they are still available through gov surplus as
field telephones.

 

[mm]

I used to have a hand cranked generator from an old phone. This puts out
exactly what you need. Think they are still available through gov surplus as
field telephones.

We had these in that 7th grade class I mentioned, but I don't think
they lend them out (and may not have them 46 years later and I
live in another city) But I'll look in surplus sources. OTOH, this
will slow down some my prospective 15 seconds per code, that I need to
finish in about 2 hours. Thanks.

Thanks a lot to you and beachcomber. It is just what I need, and the
price now ranges from 145 to 114, for the very same thing, online,
plus shipping. It's small to -- oh, yeah, you said that -- and
although that is a lot of money to fix these two things, it may have
uses in the future. OTOH, I have the specs now to do this myself, so
we'll see.

 

[Smitty Two]

OTOH, this
will slow down some my prospective 15 seconds per code, that I need to
finish in about 2 hours. Thanks.

Good grief. 15 seconds will only let you try 480 combos in two hours.
But, you should be able to do it manually in even less than 15 seconds.
In the time you've spent jabbering about it, you'd already have the damn
thing done if you'd sat down and done it. Hell, you could dial the
number once and punch in five codes in succession. Borrow a damn phone
from someone. If you're looking for pure intellectual diversion, go hook
up with that flavored coffee guy and solve the cold fusion thing instead
of trying to find a code for some five dollar answering machine that
some idiot stole and then fenced on ebay.

I used to work for a guy that could go in the machine shop and make a
piece of tooling from a sketch he scribbled on the back of an envelope
while he was taking a shit. He'd have the thing finished and working
faster than most engineers could draw it out from 12 different
perspectives with their drafting tables and t-squares and little tin
eraser guides.

This isn't a great time to be patriotic, with traitors and war criminals
running the show, but "gettin' 'er done" *is* what made this country
great, not sittin' around pondering things to death.

 

[Rich256]

I used to have a hand cranked generator from an old phone. This puts out
exactly what you need. Think they are still available through gov surplus as
field telephones.

Try ebay & search for crank phone or something similar.

 

[Michael Kennedy]

Wish someone had told me that when I was trying to build a ring circuit.

Oh well I guess I know now.


- Mike

 

[Ross Herbert]

I need to connect some telephone-type things together in my own little
circuit, and test them, but I don't know a simple method or what
voltages to use. I think I need to use some wire, some kind of DC
power, something to put a ring-signal on the line, a phone, and
whatever I am testing.

For example, I'm getting a replacement for my all-time favorite phone
answering machine, but the owner has forgotten the 3-digit code for
remote message retrieval. I'm willing to try all 900 or 1000,
probably while I'm watching tv, but only if I can get it to go
quickly. So I need a test line to ring it directly, have the machine
answer, and punch in the code.

Also I have 2 fax machines, one that sends and one that receives!
I'm pretty sure I can get it down to one that does both.

I don't have two phone lines, and even if I did, I think things would
run quicker with my own little circuit.

In the 7th grade, we had two candlestick phones and a dry cell to play
with during ham radio club, and everything worked (except it didn't
ring, but that was ok because they had no bells. )

Any help appreciated.

Since you need to find the 3 digit code for message retrieval it is
not simply a matter of generating the correct ring signal. The ring
signal needs to be received and tripped so that a normal line
connection is established with correct DC potentials etc. Only then
can you send the DTMF signals to the fax to determine the 3 digit
code. For this you will need an analog phone line simulator similar to
http://www.teltone.com/products/simulators/tls3/home.htm

Unfortunately these aren't cheap (US495 for the TLS3).

AN Australian device which will do the trick is shown here
http://www.mgram.com.au/pdf/pds22001.pdf and sells for around USD271
plus postage.

In the UK you can buy a kit to build one
http://www.hotspot.freeserve.co.uk/HOTSPOT/TLS/tlsframe.htm?lsdiag
which will be a lot cheaper than the Teltone.