Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

No worries! Should be fine!

I also have a nifty bridge for sale...

Good Luck!
Rich

"Jim Thompson" wrote in
message ...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Sounds like a joke in the making.

A Tip and a Ring go into a bar...

Seriously though, take a look here
http://en.wikipedia.org/wiki/Tip_and_ring

"Jim Thompson" wrote in message
...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably not a good idea to do that. Back in the days when the
subscriber phones had local batteries it was important. However
with the advent of no battery phones in the early 1900's it made
little difference which side was grounded. My father was an installer
and was taught in the 40's that ring/tip red/green were not critical.
Even if the tip were always ground that ground may not be the same
as the electric company's ground in your home/office as the phone
co often pounds in their own ground rod which can be many feet,
and volts, away from the electric ground rod.
Art

On Tue, 08 Feb 2011 18:26:04 -0600, flipper wrote:

On Tue, 08 Feb 2011 12:43:25 -0700, Jim Thompson
wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably about that same as assuming chandeliers, wall outlets, and
thermostats are wired properly.

Get a meter and check it.

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

"Jim Thompson" wrote in message
...

On Tue, 08 Feb 2011 18:26:04 -0600, flipper wrote:

On Tue, 08 Feb 2011 12:43:25 -0700, Jim Thompson
wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably about that same as assuming chandeliers, wall outlets, and
thermostats are wired properly.

Get a meter and check it.

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)

...Jim Thompson


No!

The lines are supposed to be floating equally above ground for full
differential pair noise reduction.

You may get line voltage spikes from either line to ground on lightning
induced faults etc.



mike

"Jim Thompson" wrote
in message ...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson
--

Neither Tip or Ring are grounded. It's a balanced Line.
Grounding either one will give you hum and allsorts of headaches.
But that may be what you want


Cheers

In article ,
says...

"Jim Thompson" wrote in message
...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably not a good idea to do that. Back in the days when the
subscriber phones had local batteries it was important. However
with the advent of no battery phones in the early 1900's it made
little difference which side was grounded. My father was an installer
and was taught in the 40's that ring/tip red/green were not critical.
Even if the tip were always ground that ground may not be the same
as the electric company's ground in your home/office as the phone
co often pounds in their own ground rod which can be many feet,
and volts, away from the electric ground rod.
Art

Well it wasn't critical until the 1960's when DTMF aka Touch Tone made
the scene. The early 35 type DTMF dials had to have the correct polarity
to function properly.

It was telco's early trick to prevent people using Touch Tone if they
didn't pay for it.

Jim Thompson writes:


What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)

Well, that was how selective ringing party lines worked. but
modern CO's use tip to ring. You can not ground tip; it is NOT
grounded except during the ring cycle. And it's not at audio ground,
period.

Unbalance the pair and you'll not hear anything but 60Hz.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

In article ,
Jim Thompson
wrote:

On Tue, 08 Feb 2011 18:26:04 -0600, flipper wrote:

On Tue, 08 Feb 2011 12:43:25 -0700, Jim Thompson
wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably about that same as assuming chandeliers, wall outlets, and
thermostats are wired properly.

Get a meter and check it.

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)

...Jim Thompson

The phone lines are a mile long antenna that can pick up a few volts of
broadband hash. You definitely don't want the pair becoming unbalanced
by any amount.
--
I will not see posts or email from Google because I must filter them as spam

"Martin Riddle" wrote in message
...


"Jim Thompson" wrote
in message ...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson
--

Neither Tip or Ring are grounded. It's a balanced Line.
Grounding either one will give you hum and allsorts of headaches.
But that may be what you want


Cheers

This is a test, Only a test.

Why is Tip called Tip and why is Ring called Ring??

First correct answer wins bragging rights.

Les

On Tue, 8 Feb 2011 13:32:52 -0800, "Artemus"
wrote:


"Jim Thompson" wrote in message
.. .
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably not a good idea to do that. Back in the days when the
subscriber phones had local batteries it was important. However
with the advent of no battery phones in the early 1900's it made
little difference which side was grounded. My father was an installer
and was taught in the 40's that ring/tip red/green were not critical.
Even if the tip were always ground that ground may not be the same
as the electric company's ground in your home/office as the phone
co often pounds in their own ground rod which can be many feet,
and volts, away from the electric ground rod.
Art



Way back when, (back to the 70s or 60s), the polarity would reverse
when the called party answered. This was called supervision or
reversal and propagated all the way back through a long distance
connection.

boB

On 2/8/2011 8:17 PM, ABLE1 wrote:
"Martin wrote in message
...


"Jim wrote
in message ...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson
--

Neither Tip or Ring are grounded. It's a balanced Line.
Grounding either one will give you hum and allsorts of headaches.
But that may be what you want


Cheers

This is a test, Only a test.

Why is Tip called Tip and why is Ring called Ring??

First correct answer wins bragging rights.

There is really not much to brag about. The answer was already
given in the Wikipedia article that Oppie posted on 2/8/2011 12:46 PM.

http://en.wikipedia.org/wiki/Tip_and_ring


Dan

T wrote:
In article ,
"Jim Thompson" wrote
in message ...
Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

Probably not a good idea to do that. Back in the days when the
subscriber phones had local batteries it was important. However
with the advent of no battery phones in the early 1900's it made
little difference which side was grounded. My father was an installer
and was taught in the 40's that ring/tip red/green were not critical.
Even if the tip were always ground that ground may not be the same
as the electric company's ground in your home/office as the phone
co often pounds in their own ground rod which can be many feet,
and volts, away from the electric ground rod.
Art

Well it wasn't critical until the 1960's when DTMF aka Touch Tone made
the scene. The early 35 type DTMF dials had to have the correct polarity
to function properly.

It was telco's early trick to prevent people using Touch Tone if they
didn't pay for it.

I was a "victim" of this once. I had just moved into a new apartment, back
when the Telco guy had to come in to hook up the phone. I finally got all
moved in, and picked up the phone to call whoever to tell them I was moved
in, and the touch-tone didn't work. I got dial tone, but when I pressed the
touch-tone buttons, all it did was blank the dialtone, and go back to
dialtone when I let the button up.

I "flashed the hookswitch (switchhook?)" - you know, in the old movies,
when they'd rattle the button or rattle that hook where the earpiece hung
on the _really_ old phones - "clickety, clickety, Hello, Operator?" - ten
times, because I knew that that was how the old dial phones worked - it
simply interrupted the current loop - and finally the operator answered.
I told her what the problem was, and she said, "Oh, sounds like polarity."

They sent out a Telco guy, who swapped the red and green leads, and I had
touch-tone. If they'd told me that that was all it needed, they could
have saved a service call, but I was but a mere customer.

I suppose I could have figured it out - I was a tech at the time, after
all, but hey, I think it was illegal to mess with your own phone back in
those days.

Cheers!
Rich

ABLE1 wrote:

This is a test, Only a test.

Why is Tip called Tip and why is Ring called Ring??


They're like the glans and prepuce[1] of the conceptually penile phone plug.

Hope This Helps!
Rich
[1] or Forced Infant Genital Mutilation scar.

On 11-02-08 05:37 PM, m II wrote:


"Jim Thompson" wrote in message
...

On Tue, 08 Feb 2011 18:26:04 -0600, flipper wrote:

On Tue, 08 Feb 2011 12:43:25 -0700, Jim Thompson
wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

...Jim Thompson

Probably about that same as assuming chandeliers, wall outlets, and
thermostats are wired properly.

Get a meter and check it.

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)

...Jim Thompson


No!

The lines are supposed to be floating equally above ground for full
differential pair noise reduction.

You may get line voltage spikes from either line to ground on lightning
induced faults etc.



mike


Nice going, you mental deficient. Drug your children yet again?

boB writes:



Way back when, (back to the 70s or 60s), the polarity would reverse
when the called party answered. This was called supervision or
reversal and propagated all the way back through a long distance
connection.

Very much depended on the office involved. Panel & XY, yes; X-bar nope.
I can't recall what step did.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

flipper wrote:

Back at ya. What is on, or off, hook called on, or off, hook?

OK, it's not my turn, but "on hook" means it's hung up, the current loop
is open circuit, and "off hook" means it's in your hand, and the current
loop switch is closed, and current is flowing.

Hope This Helps!
Rich

On Wed, 9 Feb 2011 08:39:22 +0000 (UTC), David Lesher
wrote:

boB writes:



Way back when, (back to the 70s or 60s), the polarity would reverse
when the called party answered. This was called supervision or
reversal and propagated all the way back through a long distance
connection.

Very much depended on the office involved. Panel & XY, yes; X-bar nope.
I can't recall what step did.

IIRC, step didn't reverse the line, but I don't remember the final
stages of the connector that well anymore, so it is possible it did...

Charlie
Former SxS Equipment Maintainer

On Wed, 09 Feb 2011 07:35:44 -0800, Charlie E.
wrote:

On Wed, 9 Feb 2011 08:39:22 +0000 (UTC), David Lesher
wrote:

boB writes:



Way back when, (back to the 70s or 60s), the polarity would reverse
when the called party answered. This was called supervision or
reversal and propagated all the way back through a long distance
connection.

Very much depended on the office involved. Panel & XY, yes; X-bar nope.
I can't recall what step did.

IIRC, step didn't reverse the line, but I don't remember the final
stages of the connector that well anymore, so it is possible it did...

Charlie
Former SxS Equipment Maintainer

I always thought that line-reversal (or applying a voltage) was used
to hang up a call you didn't originate.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

On 02/08/2011 07:31 PM, Jim Thompson wrote:

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)



Jim, did you finally get some useful info? Assuming that Verizon and
others for traditional analog telephone service are following the old
Western Electric (Ma Bell) standards, then the on-hook DC voltage
between Tip and Ring should be nominally 48 VDC. If you measure (either
Tip or Ring - I don't remember which one) to earth ground you will also
see 48 VDC since one side of the central office battery is connected to
earth ground. From an AC (voice frequency) standpoint both Tip and Ring
are balanced to earth ground (for hum reduction) with a nominal line/set
impedance of 600 ohms. The AC and DC aspects of the line are kept
isolated via chokes and/or repeating coils, which are required in a
common-battery (as opposed to local battery) telephone system in order
to prevent the shorting out of the audio by the central office battery.

Now in "ancient" times two-party line ringing was accomplished by
connecting the phone's ringer from Tip-to-earth ground on one
subscriber's set and from Ring-to-ground on the other subcriber's set.
This also had to be wired appropriately on the central office's ringing
equipment. Connecting subscriber set ringers in this manner adds a very
slight amount of hum due to the unbalancing of the phone line (but not
much due to the ringer coil high impedance).

AFAIK all ringing these days is bridged (ringer connected Tip-to-Ring)
so ringing-to-ground would probably not work. This is also worth
remembering if you ever desire to hook-up an antique phone (e.g. a WE
type 500 or 2500 set) to your phone line and find the ringer
non-operative (unless you want it that way). The ringer should be
connected to the incoming phone line red and green wires with no ringer
wire connected to the yellow or black one. Sincerely,

--
John Wood (Code 5520) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

"Jim Thompson" wrote in
message ...
On Wed, 09 Feb 2011 07:35:44 -0800, Charlie E.
wrote:

On Wed, 9 Feb 2011 08:39:22 +0000 (UTC), David Lesher
wrote:

boB writes:



Way back when, (back to the 70s or 60s), the polarity would reverse
when the called party answered. This was called supervision or
reversal and propagated all the way back through a long distance
connection.

Very much depended on the office involved. Panel & XY, yes; X-bar nope.
I can't recall what step did.

IIRC, step didn't reverse the line, but I don't remember the final
stages of the connector that well anymore, so it is possible it did...

Charlie
Former SxS Equipment Maintainer

I always thought that line-reversal (or applying a voltage) was used
to hang up a call you didn't originate.

Charlie is correct Jim. Polarity reversal indicated a call was answered.

Perhaps you recall the early days of third party long distance carriers...
The tone pad on the calling phone was often disabled, presumably by the
polarity reversal, which made it impossible to enter the long distance codes
for a third party carrier. Personally, I carried a pocket dialer which
stored
touch tone sequences in a calculator size device. I would hold it to the
phone
transmitter to complete the call.

In the days of fiber optic links, a polarity reversal is ancient history.

Jon





--- news://freenews.netfront.net/ - complaints: ---

On Wed, 09 Feb 2011 13:52:34 -0500, "J.B. Wood"
wrote:

On 02/08/2011 07:31 PM, Jim Thompson wrote:

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)



Jim, did you finally get some useful info? Assuming that Verizon and
others for traditional analog telephone service are following the old
Western Electric (Ma Bell) standards, then the on-hook DC voltage
between Tip and Ring should be nominally 48 VDC. If you measure (either
Tip or Ring - I don't remember which one) to earth ground you will also
see 48 VDC since one side of the central office battery is connected to
earth ground. From an AC (voice frequency) standpoint both Tip and Ring
are balanced to earth ground (for hum reduction) with a nominal line/set
impedance of 600 ohms. The AC and DC aspects of the line are kept
isolated via chokes and/or repeating coils, which are required in a
common-battery (as opposed to local battery) telephone system in order
to prevent the shorting out of the audio by the central office battery.

Now in "ancient" times two-party line ringing was accomplished by
connecting the phone's ringer from Tip-to-earth ground on one
subscriber's set and from Ring-to-ground on the other subcriber's set.
This also had to be wired appropriately on the central office's ringing
equipment. Connecting subscriber set ringers in this manner adds a very
slight amount of hum due to the unbalancing of the phone line (but not
much due to the ringer coil high impedance).

AFAIK all ringing these days is bridged (ringer connected Tip-to-Ring)
so ringing-to-ground would probably not work. This is also worth
remembering if you ever desire to hook-up an antique phone (e.g. a WE
type 500 or 2500 set) to your phone line and find the ringer
non-operative (unless you want it that way). The ringer should be
connected to the incoming phone line red and green wires with no ringer
wire connected to the yellow or black one. Sincerely,

The past... it's all coming back to me ;-)

The house has only 3-pair, but if I keep careful track of the wiring,
this will work:


TIP1-----------o------------------o
| |
RINGER1 PHONE1
| |
RING1----------)------------------o
|
|
|
TIP2-----------)------o-----------o
| | |
| RINGER2 PHONE2
| | |
RING2----------)------)-----------o
| |
| |
| |
TIP3-----------o------)-----------o
| |
FROM BLOCKERS | NO PHONE LINE CONNECTION OR PHONE
| |
RING3-----------------o-----------o

The blockers will pass ring on legitimate calls only... all 800
numbers go bye-bye ;-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

On 02/08/2011 03:20 PM, Nico Coesel wrote:
Jim
wrote:

Two lines coming in...

How much risk is it to assume that both "Tips" are essentially earth
ground potential?

You can't assume either is at ground potential.


Right, they are at frame ground potential at the central office! And,
there is no reason to be sure the two lines are from the SAME CO! Ours
are not. One is from the real CO, the other is from an RT a couple
blocks away.

Jon

Jim Thompson writes:


I always thought that line-reversal (or applying a voltage) was used
to hang up a call you didn't originate.

Nope. That's been automagic for years. Hang up for X seconds.
Step may not have had it; XB surely did. It came into being
because the Jesse James Gang's successors would call all the
bank's numbers, locking them up, THEN rob the place.

What's going away/gone is CPC; Calling Party Control. It
momentarily dropped loop current on the CALLED line when the
caller hung it.

It was there to handle the abandoned call, where you called
Microsoft Support and were put on hold for 2 years; or Bell
Repair, for that matter. It came into being with the 1A key
system "HOLD" feature, but also helped on answering machines.

But that's almost all gone; many remotes (SLC-types) have no way
to interrupt the loop current. Amazingly, the ARRIS ATA's used
by ComCrap and other cable carriers do seem to have it.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"J.B. Wood" writes:


Now in "ancient" times two-party line ringing was accomplished by
........................Bell's
connecting the phone's ringer from Tip-to-earth ground on one
subscriber's set and from Ring-to-ground on the other subcriber's set.
This also had to be wired appropriately on the central office's ringing
equipment. Connecting subscriber set ringers in this manner adds a very
slight amount of hum due to the unbalancing of the phone line (but not
much due to the ringer coil high impedance).

Unless it was a long rural loop, which was where you found many party lines...
Then the hum was an issue.

AFAIK all ringing these days is bridged (ringer connected Tip-to-Ring)
so ringing-to-ground would probably not work. This is also worth
remembering if you ever desire to hook-up an antique phone (e.g. a WE
type 500 or 2500 set) to your phone line and find the ringer
non-operative (unless you want it that way). The ringer should be
connected to the incoming phone line red and green wires with no ringer
wire connected to the yellow or black one. Sincerely,

NotBell used tuned ringers; there were FOUR plans, as I recall:

20, 30, 40, 50 Hz
22, 33, 44, 55
16.66, 33.33, 50, 66.66
16, 30, 42, 54, 66

I can no longer remember all the names....

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Jim Thompson writes:


The house has only 3-pair, but if I keep careful track of the wiring,
this will work:


TIP1-----------o------------------o
| |
RINGER1 PHONE1
| |
RING1----------)------------------o
|
|
|
TIP2-----------)------o-----------o
| | |
| RINGER2 PHONE2
| | |
RING2----------)------)-----------o
| |
| |
| |
TIP3-----------o------)-----------o
| |
FROM BLOCKERS | NO PHONE LINE CONNECTION OR PHONE
| |
RING3-----------------o-----------o

Fail....I bet.

Why not just leave the ringers on the third pair? You can either
use one side to ground, or bias: a ringer [not a tweedledeedle,
a ringer..] can be set so DC bias one polarity to inhibit it
from ringing. Pick up a Lorain Products Sub_Cycle to make the
20 Hz. you'll need.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Thu, 10 Feb 2011 00:41:24 +0000 (UTC), David Lesher
wrote:

Jim Thompson writes:


The house has only 3-pair, but if I keep careful track of the wiring,
this will work:


TIP1-----------o------------------o
| |
RINGER1 PHONE1
| |
RING1----------)------------------o
|
|
|
TIP2-----------)------o-----------o
| | |
| RINGER2 PHONE2
| | |
RING2----------)------)-----------o
| |
| |
| |
TIP3-----------o------)-----------o
| |
FROM BLOCKERS | NO PHONE LINE CONNECTION OR PHONE
| |
RING3-----------------o-----------o

Fail....I bet.

Why not just leave the ringers on the third pair? You can either
use one side to ground, or bias: a ringer [not a tweedledeedle,
a ringer..] can be set so DC bias one polarity to inhibit it
from ringing. Pick up a Lorain Products Sub_Cycle to make the
20 Hz. you'll need.

Naaaah! That works. Trace it out.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

David Lesher wrote:

Jim Thompson writes:

The house has only 3-pair, but if I keep careful track of the wiring,
this will work:

TIP1-----------o------------------o
| |
RINGER1 PHONE1
| |
RING1----------)------------------o
|
|
|
TIP2-----------)------o-----------o
| | |
| RINGER2 PHONE2
| | |
RING2----------)------)-----------o
| |
| |
| |
TIP3-----------o------)-----------o
| |
FROM BLOCKERS | NO PHONE LINE CONNECTION OR PHONE
| |
RING3-----------------o-----------o

Fail....I bet.

Why not just leave the ringers on the third pair? You can either
use one side to ground, or bias: a ringer [not a tweedledeedle,
a ringer..] can be set so DC bias one polarity to inhibit it
from ringing. Pick up a Lorain Products Sub_Cycle to make the
20 Hz. you'll need.


Digikey was selling a small ring generator module, the last time I
looked.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

"Michael A. Terrell" writes:


Pick up a Lorain Products SubCycle to make the
20 Hz. you'll need.

Digikey was selling a small ring generator module, the last time I
looked.

That's no fun; a SubCycle will make a nice hum, and it's 100%
short circuit proof; an elegant piece of magnetics...
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:

"Michael A. Terrell" writes:

Pick up a Lorain Products SubCycle to make the
20 Hz. you'll need.

Digikey was selling a small ring generator module, the last time I
looked.

That's no fun; a SubCycle will make a nice hum, and it's 100%
short circuit proof; an elegant piece of magnetics...


It's heavy and wastes energy. It's big, and the ones I have laying
around have nice, sharp corners. Not everyone likes things to hum
mindlessly. If it didn't bother anyone, there would be no need for kill
filters on usenet.

There was one in every 1A2 phone system, and I've junked about 100 of
them.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

J.B. Wood wrote:
On 02/08/2011 07:31 PM, Jim Thompson wrote:

I wasn't clear...

What I'm driving at, can I run a ringer from Ring to Earth ground?

(I don't have enough pairs :-)



Jim, did you finally get some useful info? Assuming that Verizon and
others for traditional analog telephone service are following the old
Western Electric (Ma Bell) standards, then the on-hook DC voltage
between Tip and Ring should be nominally 48 VDC. If you measure (either
Tip or Ring - I don't remember which one) to earth ground you will also
see 48 VDC since one side of the central office battery is connected to
earth ground. From an AC (voice frequency) standpoint both Tip and Ring
are balanced to earth ground (for hum reduction) with a nominal line/set
impedance of 600 ohms. The AC and DC aspects of the line are kept
isolated via chokes and/or repeating coils, which are required in a
common-battery (as opposed to local battery) telephone system in order
to prevent the shorting out of the audio by the central office battery.

Now in "ancient" times two-party line ringing was accomplished by
connecting the phone's ringer from Tip-to-earth ground on one
subscriber's set and from Ring-to-ground on the other subcriber's set.
This also had to be wired appropriately on the central office's ringing
equipment. Connecting subscriber set ringers in this manner adds a very
slight amount of hum due to the unbalancing of the phone line (but not
much due to the ringer coil high impedance).

AFAIK all ringing these days is bridged (ringer connected Tip-to-Ring)
so ringing-to-ground would probably not work. This is also worth
remembering if you ever desire to hook-up an antique phone (e.g. a WE
type 500 or 2500 set) to your phone line and find the ringer
non-operative (unless you want it that way). The ringer should be
connected to the incoming phone line red and green wires with no ringer
wire connected to the yellow or black one. Sincerely,


I've read all the answers so far looking for mentions of hum and this is
the first I've seen. As I recall, there is an earth ground rod at the
entrance, but the installer can tie it to either line of the balanced
pair to minimize hum.

Ring voltage used to be about 90 volts - can you use a bridge rectifier
feeding a voltage comparator to detect it, then some dc circuit to
ring.? 48 volts is normal idle, the phones are low enough inpedance to
drop it near 0 when off hook, but the ring voltage emulates the old
hand-cranked generators with about 90 volts AC out.

Then again, I've never worked for a phone company and haven't tried this
stuff since the 70s.

Alan

This is a pretty neat group.

J.B. Wood:

Jim, did you finally get some useful info? Assuming that Verizon and
others for traditional analog telephone service are following the old
Western Electric (Ma Bell) standards, then the on-hook DC voltage
between Tip and Ring should be nominally 48 VDC

As far as I know the Tip should be to ground (only at the central office's
side) and the Ring at -48 VDC. This was due to prevent corrosion and ion
migration.

The off-hook voltage should be between 6 and 10 V.

Alan Corey writes:


I've read all the answers so far looking for mentions of hum and this is
the first I've seen. As I recall, there is an earth ground rod at the
entrance, but the installer can tie it to either line of the balanced
pair to minimize hum.

No! If you ground tip or ring anywhere except via the line card, the
imbalance will destroy the line.

Both T & R do have a overvoltage protector that shunts to local
ground, and that is tied to the building/power ground (MGN -
Multi Ground Neutral).

Party line ringing disturbed this balance, but in theory the L-C
ringer circuit limited the imbalance.

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