help with Rotary Phone

[Kurtis]

Hi, hoping someone can help me out here.

I have a rotary phone from the 70s or 80s, and it doesn't seem to work with
dsl line filters at all.

My newer phones have no problem and it sounds good... So, is there something
else I could try to get the fuss and hiss to stop? The phone's not
defective. It's just old

Thanks
kurtis
kurtolios@hotmail.com

 

[Robert Baer]

Kurtis wrote:

Hi, hoping someone can help me out here.

I have a rotary phone from the 70s or 80s, and it doesn't seem to work with
dsl line filters at all.

My newer phones have no problem and it sounds good... So, is there something
else I could try to get the fuss and hiss to stop? The phone's not
defective. It's just old

Thanks
kurtis
kurtolios@hotmail.com

Maybe the line with DSL does not have compatible protocol.
The rotary phone worked with a line having 48V open circuit, and drew
from 6mA to 20mA when off hook (as i vaguely remember it; will measure
if you want, as i have a genuine MaBell rotary).
You could take a multimeter and measure the voltage between the DSL
lines, when all equipment (phones, computers, etc) are disconnected.
Then either measure the current when that phone is on the line (or
short circuit current).
The values you get might be instructive...

 

[Bill Janssen]

Robert Baer wrote:

Kurtis wrote:


Hi, hoping someone can help me out here.

I have a rotary phone from the 70s or 80s, and it doesn't seem to work with
dsl line filters at all.

My newer phones have no problem and it sounds good... So, is there something
else I could try to get the fuss and hiss to stop? The phone's not
defective. It's just old

Thanks
kurtis
kurtolios@hotmail.com



Maybe the line with DSL does not have compatible protocol.
The rotary phone worked with a line having 48V open circuit, and drew
from 6mA to 20mA when off hook (as i vaguely remember it; will measure
if you want, as i have a genuine MaBell rotary).
You could take a multimeter and measure the voltage between the DSL
lines, when all equipment (phones, computers, etc) are disconnected.
Then either measure the current when that phone is on the line (or
short circuit current).
The values you get might be instructive...


The current should be 20 mA or more when off hook.

Is there a low pass filter on the phone line after the DSL splitter?
There should be a phone line
device that keeps the DSL signals from the phone.

If the above is OK then I think you have a defective phone.

Bill K7NOM

 

[John Miles]

In article <a686c665.0408021725.19bf714d@posting.google.com>,
spudnuty@lycos.com says...

Hey Kurtis,

I Googled this because I have clients with rotary phones (retro they
like the ring or like Carrie in Sex in the City )
Suprisingly I came up with this:
"Be aware, if you have a wall-mounted phone or an older rotary phone,
you must buy a different type of filter." its at
http://www.waymark.net/dsl_zoom2.html
Is it because these phones have a transformer in them that defeats the
regular filter?

One data point, for what it's worth -- our Western Electric 302 gets
along fine with DSL. Our house has got to be pushing the residental
ringer-equivalence limit, with three cordless phones and the WE302.

I'm not sure why the filters would be so load-sensitive. I'd expect the
older phones to look more inductive than newer phones with solid-state
hybrid networks, but that shouldn't bother the DSL filters. In fact,
I'm sort of surprised that DSL hash would make it through the old-school
hybrids at all, even without a filter.

-- jm ("We're sorry, the number you have dialed is imaginary. Please
rotate your telephone 90 degrees and place your call again.")

------------------------------------------------------
http://www.qsl.net/ke5fx
Note: My E-mail address has been altered to avoid spam
------------------------------------------------------

 

[Fred McKenzie]

<< "Kurtis" <kurtolios@hotmail.com> wrote:

I have a rotary phone from the 70s or 80s, and it doesn't seem to work with
dsl line filters at all.

My newer phones have no problem and it sounds good... So, is there something
else I could try to get the fuss and hiss to stop?

Kurtis-

PF is probably right about the DSL filter. However, there is another problem
with older phones. The microphone element uses carbon granules that are
compressed by sound waves so resistance varies as you speak. An AC voltage is
generated from a DC bias current flowing through the varying resistance of the
element.

The problem is that this is a noisy process. There are various pops and hisses
that can occur. It sometimes gets especially bad when the granules become
caked. You sometimes can make it better by banging the handset against
something hard like a tabletop. This frees-up the carbon granules, making the
microphone work better.

Fred