Any way to cut telephone crosstalk?

[Don Taylor]

Wall jack, 4 foot cord, internal modem, 4 foot cord, telephone.

If it is a "newer" phone, the 6 ounce plastic pushbutton kind,
I pick up the handset, dial 1 and listen there is LOUD crosstalk.

If I unplug that and go dig out my ancient old ITT bell rotary 3 pound
desk phone from decades ago and try the same there is NO crosstalk.

(And I think this might be contributing to noise with the modem,
loss of connections now and then, etc)

Any bright ideas about what I might to combat some of this?
Use the cord to make a wrap or two around a ferrite torroid?
Anything else? (cheap new phone is line powered, not wall powered)

Thanks

 

[Jerry G.]

The only thing I can think of, is that your phone is not wired correctly, or
does not meet proper standards for your telephone company.

Is this a phone that is approved by your telephone company? Or, is this one
of these cheap bargain phones?

--

Jerry G.
=====

Wall jack, 4 foot cord, internal modem, 4 foot cord, telephone.

If it is a "newer" phone, the 6 ounce plastic pushbutton kind,
I pick up the handset, dial 1 and listen there is LOUD crosstalk.

If I unplug that and go dig out my ancient old ITT bell rotary 3 pound
desk phone from decades ago and try the same there is NO crosstalk.

(And I think this might be contributing to noise with the modem,
loss of connections now and then, etc)

Any bright ideas about what I might to combat some of this?
Use the cord to make a wrap or two around a ferrite torroid?
Anything else? (cheap new phone is line powered, not wall powered)

Thanks

 

[CWatters]

Wall jack, 4 foot cord, internal modem, 4 foot cord, telephone.

If it is a "newer" phone, the 6 ounce plastic pushbutton kind,
I pick up the handset, dial 1 and listen there is LOUD crosstalk.

If you call someone with this handset can they hear the cross talk as well?
eg is it really cross talk or just a noisy on your handset speaker?

 

[Ken Taylor]

Wall jack, 4 foot cord, internal modem, 4 foot cord, telephone.

If it is a "newer" phone, the 6 ounce plastic pushbutton kind,
I pick up the handset, dial 1 and listen there is LOUD crosstalk.

If I unplug that and go dig out my ancient old ITT bell rotary 3 pound
desk phone from decades ago and try the same there is NO crosstalk.

(And I think this might be contributing to noise with the modem,
loss of connections now and then, etc)

Any bright ideas about what I might to combat some of this?
Use the cord to make a wrap or two around a ferrite torroid?
Anything else? (cheap new phone is line powered, not wall powered)

Thanks

When you say 'cross-talk', is it other people's conversations or echoes?
Does it happen with handset plugged straight into the wall jack? Are there
any other extension sockets on your line in your house?

Ken

 

[Don Taylor]

If you call someone with this handset can they hear the cross talk as well?
eg is it really cross talk or just a noisy on your handset speaker?

They can hear it too but not at a lower volume than here

And I loved the comment about whether this was a certified phone or not.
When was the last time your phone company came out and did product
certification?

 

[CWatters]

And I loved the comment about whether this was a certified phone or not.
When was the last time your phone company came out and did product
certification?

Many countries have a certification scheme. In the UK telecoms products used
to (still?) carry a green triangle or a red circle lable to indicate
compliance with that scheme.

 

[petrus bitbyter]

Wall jack, 4 foot cord, internal modem, 4 foot cord, telephone.

If it is a "newer" phone, the 6 ounce plastic pushbutton kind,
I pick up the handset, dial 1 and listen there is LOUD crosstalk.

If I unplug that and go dig out my ancient old ITT bell rotary 3 pound
desk phone from decades ago and try the same there is NO crosstalk.

(And I think this might be contributing to noise with the modem,
loss of connections now and then, etc)

Any bright ideas about what I might to combat some of this?
Use the cord to make a wrap or two around a ferrite torroid?
Anything else? (cheap new phone is line powered, not wall powered)

Thanks

Crosstalk is about unwanted signal transfer between two (telephone)lines, so
two sets of wires. So what other line do you hear after dialing that 1?
Can't imagine crosstalk in the last 4 foot cord where you are the only user.
So what do you hear? Yourself? Then most likely the antilocalcircuit in your
phone is broken. The old machines used transformers that are almost
undestructable but the new electronic circuits are more sensitive. Other
possibilties are wrong wiring and bad contacts.

Do you achieve the same result if you keep the modemcard out? Then the above
stands. If not, you have to look for more precisely for bad contacts between
phone and modem. That RJxx jackets sometimes get lame contacts. The plug
also can be damaged. I met both cases several times.

If you really hear another line, it's almost sure the impedance matching
between line and phone is very bad. Most likely some circuit in the phone
became defective although wrong wiring and bad contacts are also a possible
cause (as always).

petrus bitbyter

 

[Don Taylor]

....
When you say 'cross-talk', is it other people's conversations or echoes?
Conversations

Does it happen with handset plugged straight into the wall jack?

Yes, and even when I try it outside at the terminal block.

Are there any other extension sockets on your line in your house?

No

 

[Don Taylor]

Many countries have a certification scheme. In the UK telecoms products used
to (still?) carry a green triangle or a red circle lable to indicate
compliance with that scheme.

I don't mean to be sarcastic about this but when AT&T sells itself
and all the providers in the country seem to have realized that
they can make LOTS more money trading cell phone contracts than they
can making telephones... I suspect whoever might be left in the little
office somewhere who's job it was to certify compliance just might
have turned out the light and been outsourced without anybody noticing.

 

[Don Taylor]

dont posted:
<< They can hear it too but not at a lower volume than here

What is "it?" Static, echo, CB radio, AM broadcast radio, buzz, hum, etc.
Until we know that, there is no realistic way to sort out what is the problem.

I was answering the question I was asked, "can the person on the other
end of the phone hear this same conversation that I'm hearing or is
it strictly limited to my end.

<< And I loved the comment about whether this was a certified phone or not.
When was the last time your phone company came out and did product
certification?

Whether or not it is Certified may give a clue to the problem. I'm sure the
person who posted the question is glad you enjoyed the question. If you are so
smugly smart why did you post your cross-talk problem?

Well, I was thinking someone might have a list of moderately simple
techniques that could kill the noise, I searched and didn't find
any such list, before I even asked the question.

Having now checked ALL the phones I have here and there the ONLY
certification I can see on any one of them is that a couple claim
they comply with Part 68, which if I remember correctly is that
they aren't supposed to radiate enough to interfere with anything
else but unless I've forgotten Part 68 said nothing about a device
not being interfered WITH. (And the old "real AT&T phone" has a
ringer equivalency, but that seems like it went out of style about
the time AT&T lost the ruling against Dataphone and connecting
anything other than AT&T equipment to the line. I can remember
getting a letter from the phone company 30 years ago when they did
a ringer sweep of the town and sent warning letters to everyone who
had a greater load than the number of phones they were paying for.)

So what's the certification ruling about phones not being subject
to cross talk? I 'm curious. We've got a federal documents
repository downtown and I'll go look it up.

Thank you

 

[Don Taylor]

Crosstalk is about unwanted signal transfer between two (telephone)lines, so
two sets of wires. So what other line do you hear after dialing that 1?
Can't imagine crosstalk in the last 4 foot cord where you are the only user.
So what do you hear? Yourself? Then most likely the antilocalcircuit in your
phone is broken. The old machines used transformers that are almost
undestructable but the new electronic circuits are more sensitive. Other
possibilties are wrong wiring and bad contacts.

Conversation from somewhere else, that was why I called it crosstalk
rather than echo. And as I said, identical results if I take the pair
of phones outside to the terminal block and repeat the experiment there
with no inside wiring, no modem, no computer.

Do you achieve the same result if you keep the modemcard out? Then the above
stands. If not, you have to look for more precisely for bad contacts between
phone and modem. That RJxx jackets sometimes get lame contacts. The plug
also can be damaged. I met both cases several times.

I've looked at jack and plug, both appear to be clean, not corroded,
not badly bent, pretty good looking to me.

If you really hear another line, it's almost sure the impedance matching
between line and phone is very bad. Most likely some circuit in the phone
became defective although wrong wiring and bad contacts are also a possible
cause (as always).

By eliminating all the inside wiring and the computer and everything
to the outside jack, and the problem persists, it seems like we are
getting closer to the problem. But I'm still not seeing any solution
other than going back to the 1970's Bell rotary desk phone, yet.

thanks

 

[CWatters]

I don't mean to be sarcastic about this but when AT&T sells itself
and all the providers in the country seem to have realized that
they can make LOTS more money trading cell phone contracts than they
can making telephones... I suspect whoever might be left in the little
office somewhere who's job it was to certify compliance just might
have turned out the light and been outsourced without anybody noticing.

I might be wrong but I think it's been "self certification" in the UK for
some years.

 

[CWatters]

If you get the same problem when you move the phone to another socket then
it sounds like the phone is faulty. Unless it's some fancy telephone I
would just trash it.

 

[Noah Little]

By eliminating all the inside wiring and the computer and everything
to the outside jack, and the problem persists, it seems like we are
getting closer to the problem. But I'm still not seeing any solution
other than going back to the 1970's Bell rotary desk phone, yet.

You've now given us information to know how to solve the problem: get
rid of the defective phone.

 

[petrus bitbyter]

Conversation from somewhere else, that was why I called it crosstalk
rather than echo. And as I said, identical results if I take the pair
of phones outside to the terminal block and repeat the experiment there
with no inside wiring, no modem, no computer.


I've looked at jack and plug, both appear to be clean, not corroded,
not badly bent, pretty good looking to me.


By eliminating all the inside wiring and the computer and everything
to the outside jack, and the problem persists, it seems like we are
getting closer to the problem. But I'm still not seeing any solution
other than going back to the 1970's Bell rotary desk phone, yet.

thanks

Well,

That third party conversation is picked up somewhere along the line. Most
likely on a place the lines are running parallel over some distance. Your
line looks like an antenna that picks up the radiation from the other line.
Most likely the cause is lack of correct termination on the phones side if
there is some termination at all. Maybe the internal state of the phone
changes after pressing the 1, maybe the exchange makes some connection when
you do. Nevertheless, your phone is either defective or suffers from a
design flaw. You can open it and look for broken contacts or bad solder
joints but with low chance for succes. You could try to put a resistor in
the phone to correct termination but I can't be sure to tell where and how
even if I have the phone in my own hands. (If you knew you should not have
to put the question in the first place.) You can buy or borrow another phone
just to check your findings. Think you have to buy another one anyway if you
want to get rid of that crosstalk. They are not that expensive after all.

petrus bitbyter

 

[[email protected]]

(snip)

Your problem is in the phone company lines. I had the exact same
problem. Call the company and report what is happening. Good luck.

 

[Allan Adler]

How do you know it is cross talk and not some other signal,
such as a radio station's talk show?

A few years ago, I had a phone which seemed also to pick up a radio
station. It was so bad that when I tried to use it to dial up my ISP,
the computer said it couldn't find the dial tone. The problem was solved
by using a filter from Radio Shack. I only used the filter with the computer,
so I don't know whether it would have improved the sound quality if I had
used it with the phone.

Usually I consider it an act of desperation to buy anything from Radio Shack,
and it was certainly one in this case, but they actually had a solution when
no one else did.

 

[Don Taylor]

How do you know it is cross talk and not some other signal,
such as a radio station's talk show?

From the conversation going on it is going to be one personal
talk show!

A few years ago, I had a phone which seemed also to pick up a radio
station. It was so bad that when I tried to use it to dial up my ISP,
the computer said it couldn't find the dial tone. The problem was solved
by using a filter from Radio Shack. I only used the filter with the computer,
so I don't know whether it would have improved the sound quality if I had
used it with the phone.

The elderly friend of mine who kept telling me he had this problem,
and I kept dismissing it as just one more example of elderly
crankiness.. until I happened to drive the 40 miles to go see him,
tried to make a call and the conversation on the phone line was
louder than usual phone conversations! And that was after dialing
a single digit to just silence the dial tone. And his hearing/
tinnitus is worse than mine. No wonder he had complained.

Usually I consider it an act of desperation to buy anything from Radio Shack,
and it was certainly one in this case, but they actually had a solution when
no one else did.

Now a filter sounds like a possibility. Have you got more details
about what I'm supposed to look for? The last time I went in looking
for parts at Radio Shack the minute they realized I wasn't going
to make them a cell phone contract commission they went back to
talking among themselves.

And, I have an honest suggestion, for the folks who discussed
"certified" phones. Choose a phone supplier, you get to pick the
one that you think has the best chance. The next time you might
be there, ask the salesman if the phone is really "certified" and
see if they can tell you something to make you believe they actually
know what they are talking about. To be honest I would be REALLY
surprised if they know what you are talking about and even more
surprised if they can actually show anything that confirms this.
Please report back, I would love to hear what the outcome was.

Someone suggested the phone company would sell "certified" phones
and I should buy one of those. I honestly wouldn't think that Qwest
or Verizon even sells non-cell phones any more, I'll call them up
and tell them I want to buy one of the certified ones and see what
happens. But before I started this I did call and they offered to
come check the inside wiring ($50 plus hourly I think)

I worked for Tek decades ago and we had our own EMI cert lab, but
I never did any cert work. I wonder if they dumped that long ago,
along with the 80% of the workforce.

Thanks

 

[Ken Taylor]

Yes, and even when I try it outside at the terminal block.


No

Okay, your problem is in the telco wiring, most likely a high-resistance
joint (or water in a cable pit somewhere). Call them and get it fixed.

Ken

 

[Ken Taylor]

Okay, your problem is in the telco wiring, most likely a high-resistance
joint (or water in a cable pit somewhere). Call them and get it fixed.

Ken

Incidentally, FWIW, if you tell the telco that you hear other conversations
they generally react faster than if you just say it's noisy or your modem
doesn't train up nicely. Privacy, and all that.

Cheers.

Ken