Weird telephone problem

[David Nebenzahl]

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[David Nebenzahl]

On 7/16/2010 2:54 PM David Nebenzahl spake thus:

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

Forgot to mention, in case it's relevant, that they also have DSL, and
some of the phones have in-line DSL filters. Problem remains with or
without the filters.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[Dave Platt]

In article <4c40d4c0$0$2401$822641b3@news.adtechcomputers.com>,
David Nebenzahl <nobody@but.us.chickens> wrote:

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

That sounds to me as if the circuit has developed a "DC open", which
still has some small amount of capacitive coupling through it.

The central office won't "see" that the phones have gone off-hook, and
initiate a dial tone, unless the phone draws at least a few milliamps
of DC current from the line. If corrosion or a wire break has
interrupted one side or the other of the line, the phone wouldn't be
able to draw DC current through it, and wouldn't trigger the off-hook
detector at the central office.

Ringing is a different issue, as it involved higher voltages, AC (or
pulsed-DC), and is handled differently by different sorts of phones.
The ringing signal here in the U.S. is somewhere around 100 volts at
20 Hz, if I recall correctly. Real old-fashioned phones with real
ringers have an electromagnet/solenoid ringer, coupled to the line via
a large-value capacitor (agian, if I recall correctly) and they
require a significant amount of ringer current to operate.

Phones with electronic ringers... and wireless phones in particular...
operate differently. They really don't need to draw much current from
the ringing line in order to detect a ring... all a wireless-phone
base station may need to do is monitor the phone-line voltage with a
high-impedance voltage sensor, and "tell" the handsets to ring when it
sees a high voltage.

My guess is that: (1) you've got a broken wire or corroded connection
in the path which feeds the phones that no longer work, and (2)
there's enough leakage through the break to allow the wireless handset
to detect the high-voltage AC which means "ringing". Hence, the
wireless handset is told to ring. However, when you try to answer the
call, the wireless station base tries to connect to the line and start
drawing the normal amount of loop current... and it can't do so
because of the near-total break in the wire.

Try using one of those red-and-green-LED "phone line voltage and
polarity" detectors. I suspect you'll find that it doesn't light
(either color) when plugged into one of the dead outlets, but that if
you phone the house number from outside the LED will flash at least
slightly due to a small amount of AC leakage past the broken connection.

Start looking for bad splices, broken wires in junction boxes, or
places where rats or mice have chewed on the wiring.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Bill Janssen]

Dave Platt wrote:

In article <4c40d4c0$0$2401$822641b3@news.adtechcomputers.com>,
David Nebenzahl <nobody@but.us.chickens> wrote:


Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?


That sounds to me as if the circuit has developed a "DC open", which
still has some small amount of capacitive coupling through it.

The central office won't "see" that the phones have gone off-hook, and
initiate a dial tone, unless the phone draws at least a few milliamps
of DC current from the line. If corrosion or a wire break has
interrupted one side or the other of the line, the phone wouldn't be
able to draw DC current through it, and wouldn't trigger the off-hook
detector at the central office.

Ringing is a different issue, as it involved higher voltages, AC (or
pulsed-DC), and is handled differently by different sorts of phones.
The ringing signal here in the U.S. is somewhere around 100 volts at
20 Hz, if I recall correctly. Real old-fashioned phones with real
ringers have an electromagnet/solenoid ringer, coupled to the line via
a large-value capacitor (agian, if I recall correctly) and they
require a significant amount of ringer current to operate.

Phones with electronic ringers... and wireless phones in particular...
operate differently. They really don't need to draw much current from
the ringing line in order to detect a ring... all a wireless-phone
base station may need to do is monitor the phone-line voltage with a
high-impedance voltage sensor, and "tell" the handsets to ring when it
sees a high voltage.

My guess is that: (1) you've got a broken wire or corroded connection
in the path which feeds the phones that no longer work, and (2)
there's enough leakage through the break to allow the wireless handset
to detect the high-voltage AC which means "ringing". Hence, the
wireless handset is told to ring. However, when you try to answer the
call, the wireless station base tries to connect to the line and start
drawing the normal amount of loop current... and it can't do so
because of the near-total break in the wire.

Try using one of those red-and-green-LED "phone line voltage and
polarity" detectors. I suspect you'll find that it doesn't light
(either color) when plugged into one of the dead outlets, but that if
you phone the house number from outside the LED will flash at least
slightly due to a small amount of AC leakage past the broken connection.

Start looking for bad splices, broken wires in junction boxes, or
places where rats or mice have chewed on the wiring.


Good advice above

I want to add. you should see about 52 Volts on an idle line and 25
milliamp or greater current when off hook
I think to telephone switch will work on 20 milliamp, but that is
pushing it.The voltage isn't critical but the current is

Bill K7NOM

 

[Robert Macy]

On Jul 16, 2:54 pm, David Nebenzahl <nob...@but.us.chickens> wrote:

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

Had this happen to me too. Also had a pair of what looked like
excellent wires go noisy on me every time it got damp outside! had to
re-run that section of phone line inside the house walls.

The failure is probably caused by corrosion at a junction/connection.
Opens up the lines in DC, no dial tone, etc. But ringing works.

The corrosion is very slight and just enough to prevent the low
voltage to get to the phone and the telephone service company can't
recognize that you're OFF Hook, but the 90V of ringing pops across the
corrosion barrier, actually breaking it temporarily down as an arc
over [that's my opinion] then when you lift the phone, nothing. If
you called the number the sequence for me was:
At the dead phone:
1) dead phone rings
2) answer the line, no one there!
for the caller:
1) hear a ringing indication [may, or may not synchronize with actual
ringing]
2) then it's as though someone answered and hung up.

The fix, redo every junction between where the lines are good right up
to the phone. If you're lucky, it'll be at the junction box near the
phone itself. Don't do this while phones may ring, 90V hurts! Don't
sever any wires, because junctions ALWAYS fail. But if the wire is
protected, it's ok to scrape a little insulation back to check for
voltage on the line, stand by voltage is around -48, yeah sure. I
used to scrape back insulation and connect a phone to check. It was
easier than using a meter. You'll probably repair everything by
simply wiggling all the connections. I found that a good mechanicl
manipulation fixed everything to last about a year before the system
failed again.

Check FCC Part 68, which later became IEEE ???? spec, for the
operating envelope of what constitutes ON Hook and OFF Hook and all
the allowed leakages and unbalances.

Back in the '84 I wrote an article for Gernsbach which was published
in spin off to Popular Electronics an article entitled "Hands Free
Telephone" If you can find a copy there's a bit of tutorial about
Public Telephone Lines, voltages, impedances, etc. My copy's in
storage and my brain...uh, what was I saying?

 

[Dani]

The easiest fix is to go to where the phone line enters the house
(inside), unhook everything inside, & try a phone there. This will
eliminate all the inside. If it works, try hooking up one line inside
at a time to see which one's bad. Or, just get a cheap codless phone,
if it's too hard to redo all the inside wires if that's the problem.
If, for example, you have just sprayed for insects, you may have
killed a line jack, dampness can also do this. If it still won't work
the problem is outside. The phone company will generally fix the
outside gear (theirs) for free. Hope this helps.

 

[Wild_Bill]

I agree with the other suggestions of poor or corroded connections, because
I had a similar situation a number of years ago.

Intermittent ringing and noisy connections any time it would rain. The
service guy would show up within a couple of days, when it wasn't raining,
and find no problems.

This went on for months, and I had installed all new interior wiring (from
the network box terminals) and new wall jacks, so I was certain the problem
wasn't inside.

Finally, about 4 guys showed up, and after wandering around up 'n down the
street, finally determined that there was corrosion in the jack in the
network box that was making it very sensitive to moisture (probably about a
$1 part for the telco), after numerous attempts of troubleshooting and
finding no problems.

Punchblocks in damp locations (basements etc) can also be sources of
corrosion related problems.

If you don't know the age of the wall jacks, it's best to replace them all
with quality jacks, so you know that the connections are clean and secure at
each jack. A little dust and moisture/humidity (or an insect) can lead to
serious oxidation or corrosion problems over time.

--
Cheers,
WB
..............


"David Nebenzahl" <nobody@but.us.chickens> wrote in message
news:4c40d4c0$0$2401$822641b3@news.adtechcomputers.com...

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with a
good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[David Nebenzahl]

On 7/16/2010 7:20 PM Dani spake thus:

The easiest fix is to go to where the phone line enters the house
(inside), unhook everything inside, & try a phone there.

How the hell will this help me? Didn't you read my post? I said that
*some* of the phones (meaning the wiring inside the house) work and some
of them don't, so obviously the problem is inside the house.

This will eliminate all the inside. If it works, try hooking up one
line inside at a time to see which one's bad. Or, just get a cheap
codless phone, if it's too hard to redo all the inside wires if
that's the problem. If, for example, you have just sprayed for
insects, you may have killed a line jack, dampness can also do this.
If it still won't work the problem is outside. The phone company will
generally fix the outside gear (theirs) for free. Hope this helps.

Nope. It doesn't.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[Jeffrey D Angus]

David Nebenzahl wrote:

I said that *some* of the phones (meaning the wiring inside the
house) work and some of them don't, so obviously the problem
is inside the house.

Bite the bullet. Buy a box of Cat-3 (or 5) wire and start over.
Every house I've ever worked on has a total cluster-f**k for the
telephone wiring.

Pick a location, (a closet or such) and call that "home".
Run a new cable from the telephone company POE, to there.
From there, run a new cable to each and every jack in the
house.

One Type-66 split block and a package of jumper clips will
make a nice "distribution" point in the closet.

Problem solved.

And if you decide to get campy and put in a cheap PBX, all
your work is already done for the most part.

Jeff



--
“Egotism is the anesthetic that dulls the pain of stupidity.”
Frank Leahy, Head coach, Notre Dame 1941-1954

http://www.stay-connect.com

 

[David Nebenzahl]

On 7/17/2010 8:56 AM Jeffrey D Angus spake thus:

David Nebenzahl wrote:

I said that *some* of the phones (meaning the wiring inside the
house) work and some of them don't, so obviously the problem
is inside the house.

Bite the bullet. Buy a box of Cat-3 (or 5) wire and start over.
Every house I've ever worked on has a total cluster-f**k for the
telephone wiring.

Pick a location, (a closet or such) and call that "home".
Run a new cable from the telephone company POE, to there.
From there, run a new cable to each and every jack in the
house.

One Type-66 split block and a package of jumper clips will
make a nice "distribution" point in the closet.

Problem solved.

And if you decide to get campy and put in a cheap PBX, all
your work is already done for the most part.

Well, good suggestions all.

But thanks but no thanks; I'll answer several replies here by saying
that even though I posted this query, I have no intention of actually
trying to fix it. Here's why.

Mainly 'cuz I'm not a telephone repair person. As I get older I try more
and more to recognize and respect my limitations. I'm not a master of
all trades. I *might* be able to fix this problem; after all, telephone
wiring is not exactly rocket science. But still, it has its on
specialized problems, and I have no test equipment to perform this kind
of diagnosis, apart from a VOM.

Plus it's a fairly large house, with lots of wiring inside walls and in
barely-accessible crawlspaces. Not my idea of fun at all, brushing aside
piles of old rat shit to trace a wire.

Plus, the existing wiring is a total fucking mess. Unbelievable how
those phone co. monkeys wire stuff. There's a literal rat's nest of
wiring under the house, not in any box, splices every which way, no
consistency in the use of color pairs, no labels, just a fucking
nightmare. So I'll leave it to someone else to sort out, thank you very
much.

Ackshooly, the homeowners are lucky, because the last time they called
the telco (AT&T), they got a guy who scurried about under the house,
found the problem (this was a DSL issue), fixed it, and DIDN'T CHARGE
THEM ANYTHING FOR IT! They think they can get this person to perform
another miracle for them.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[PeterD]

On Sat, 17 Jul 2010 11:33:24 -0700, David Nebenzahl
<nobody@but.us.chickens> wrote:

...
Ackshooly, the homeowners are lucky, because the last time they called
the telco (AT&T), they got a guy who scurried about under the house,
found the problem (this was a DSL issue), fixed it, and DIDN'T CHARGE
THEM ANYTHING FOR IT! They think they can get this person to perform
another miracle for them.

That would truely be a miracle, and if it happens they should also
consdier buying a handful of lottery tickets. Heck, just one lottery
ticket, it will win.

 

On Sat, 17 Jul 2010 11:33:24 -0700, David Nebenzahl
<nobody@but.us.chickens> wrote:

On 7/17/2010 8:56 AM Jeffrey D Angus spake thus:

David Nebenzahl wrote:

I said that *some* of the phones (meaning the wiring inside the
house) work and some of them don't, so obviously the problem
is inside the house.

Bite the bullet. Buy a box of Cat-3 (or 5) wire and start over.
Every house I've ever worked on has a total cluster-f**k for the
telephone wiring.

Pick a location, (a closet or such) and call that "home".
Run a new cable from the telephone company POE, to there.
From there, run a new cable to each and every jack in the
house.

One Type-66 split block and a package of jumper clips will
make a nice "distribution" point in the closet.

Problem solved.

And if you decide to get campy and put in a cheap PBX, all
your work is already done for the most part.

Well, good suggestions all.

But thanks but no thanks; I'll answer several replies here by saying
that even though I posted this query, I have no intention of actually
trying to fix it. Here's why.

WTF!!!

Here's how life works. If a man (I'm referring to a real man, not
some elitest bullshit "I don't want to get my hands dirty" type who
happens to possess a Y chromosome) sees a problem, he tries to fix it.
If he can't he asks for help.

This doesn't reflect unfavorably on his masculinity. When the first
proto cave-man decided it would be nice to live in a cave rather than
get wet every time it rained, he asked his proto cave-man buddies for
advice on getting the wild animals out of the cave of choice. And
being real men, they probably offered to help. And sat around in the
cave afterward eating the former four legged occupant.

If you are going to ask for advice that you don't intend to use, the
honorable thing to do is to tell us up front that this is purely for
informational purposes. At a mimimum, afterwards say "Thanks, the
problem has been solved." That at least give your helpers the
satisfaction of having spent their time in a useful matter.

This "I'm not going to do anything about it" is BULLSHIT!!!

PlainBill

Mainly 'cuz I'm not a telephone repair person. As I get older I try more
and more to recognize and respect my limitations. I'm not a master of
all trades. I *might* be able to fix this problem; after all, telephone
wiring is not exactly rocket science. But still, it has its on
specialized problems, and I have no test equipment to perform this kind
of diagnosis, apart from a VOM.

Plus it's a fairly large house, with lots of wiring inside walls and in
barely-accessible crawlspaces. Not my idea of fun at all, brushing aside
piles of old rat shit to trace a wire.

Plus, the existing wiring is a total fucking mess. Unbelievable how
those phone co. monkeys wire stuff. There's a literal rat's nest of
wiring under the house, not in any box, splices every which way, no
consistency in the use of color pairs, no labels, just a fucking
nightmare. So I'll leave it to someone else to sort out, thank you very
much.

Ackshooly, the homeowners are lucky, because the last time they called
the telco (AT&T), they got a guy who scurried about under the house,
found the problem (this was a DSL issue), fixed it, and DIDN'T CHARGE
THEM ANYTHING FOR IT! They think they can get this person to perform
another miracle for them.

 

[David Nebenzahl]

On 7/17/2010 4:20 PM PlainBill47@yahoo.com spake thus:

If you are going to ask for advice that you don't intend to use, the
honorable thing to do is to tell us up front that this is purely for
informational purposes. At a mimimum, afterwards say "Thanks, the
problem has been solved." That at least give your helpers the
satisfaction of having spent their time in a useful matter.

This "I'm not going to do anything about it" is BULLSHIT!!!

I'm sorry you were offended.

No, I take that back: I'm actually *happy* that you were offended.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[Andrew Rossmann]

In article <4c40d4c0$0$2401$822641b3@news.adtechcomputers.com>,
nobody@but.us.chickens says...

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

You didn't mention this: What happens if you move a non-working phone to
where a working phone is? Does it now work? If so, then it's a wiring
issue. Otherwise, it's the phone itself.

Also, if you have the newer interface where the phone company connects
to the house that has RJ jacks in it, take all of the phones to it and
test them with that jack.

--
If there is a no_junk in my address, please REMOVE it before replying!
All junk mail senders will be prosecuted to the fullest extent of the
law!!
http://home.comcast.net/~andyross

 

[David Nebenzahl]

On 7/18/2010 5:46 AM Andrew Rossmann spake thus:

In article <4c40d4c0$0$2401$822641b3@news.adtechcomputers.com>,
nobody@but.us.chickens says...

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

You didn't mention this: What happens if you move a non-working phone to
where a working phone is? Does it now work? If so, then it's a wiring
issue. Otherwise, it's the phone itself.

Well, I didn't test that, but I did the reverse test which shows that
the problem is the wiring, not the phone: I took a working phone (a
regular, non-cordless phone) and plugged it in to a non-working phone
jack. It was dead, so the problem appears to me to be the wiring.

The phone that rang on an incoming call, by the way, was a cordless
(i.e., powered) phone, which tends to confirm the diagnosis someone else
here gave of a "DC open", a corroded connection that would pass enough
of the higher ring voltage to make the phone ring, but not enough to go
"off hook".


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

 

[nesesu]

On Jul 18, 12:11 pm, David Nebenzahl <nob...@but.us.chickens> wrote:

On 7/18/2010 5:46 AM Andrew Rossmann spake thus:





In article <4c40d4c0$0$2401$82264...@news.adtechcomputers.com>,
nob...@but.us.chickens says...

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

You didn't mention this: What happens if you move a non-working phone to
where a working phone is? Does it now work? If so, then it's a wiring
issue. Otherwise, it's the phone itself.

Well, I didn't test that, but I did the reverse test which shows that
the problem is the wiring, not the phone: I took a working phone (a
regular, non-cordless phone) and plugged it in to a non-working phone
jack. It was dead, so the problem appears to me to be the wiring.

The phone that rang on an incoming call, by the way, was a cordless
(i.e., powered) phone, which tends to confirm the diagnosis someone else
here gave of a "DC open", a corroded connection that would pass enough
of the higher ring voltage to make the phone ring, but not enough to go
"off hook".

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)- Hide quoted text -

- Show quoted text -

There is probably a break in L1 or L2 at a daisy chained jack. Down
stream of the break, there is no DC path for loop current to trigger
dial tone, BUT, since the ringer is AC, there can be a path back
through the ringer of a phone bridging the break [effectively two
phones in series] so the phone could ring, but not close the DC loop
when taken off hook.

Neil S.

 

[Robert Macy]

On Jul 18, 2:08 pm, nesesu <neil_sutcli...@telus.net> wrote:

On Jul 18, 12:11 pm, David Nebenzahl <nob...@but.us.chickens> wrote:





On 7/18/2010 5:46 AM Andrew Rossmann spake thus:

In article <4c40d4c0$0$2401$82264...@news.adtechcomputers.com>,
nob...@but.us.chickens says...

(And by telephone I mean the kind God intended us to use, a regular old
land line, not those Dick Tracy cell-phone thingies.)

Client has a bunch of phones in their house. Starting a few days ago,
several of them don't work; pick them up, no dial tone. (Confirmed with
a good set which I used to test all the jacks.)

But get this: while I was there, at least one of the phones that doesn't
work (a wireless phone) rang on an incoming call. WTF?!?!? It rang, but
when picked up--nothing, dead. No dial tone trying to make a call.

Anyone familiar with the inner mysteries of the telephone system care to
try to 'splain this? How could a phone not work, but still ring on an
incoming call?

You didn't mention this: What happens if you move a non-working phone to
where a working phone is? Does it now work? If so, then it's a wiring
issue. Otherwise, it's the phone itself.

Well, I didn't test that, but I did the reverse test which shows that
the problem is the wiring, not the phone: I took a working phone (a
regular, non-cordless phone) and plugged it in to a non-working phone
jack. It was dead, so the problem appears to me to be the wiring.

The phone that rang on an incoming call, by the way, was a cordless
(i.e., powered) phone, which tends to confirm the diagnosis someone else
here gave of a "DC open", a corroded connection that would pass enough
of the higher ring voltage to make the phone ring, but not enough to go
"off hook".

--
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with the flaunting of well-defined muscle, wrapped in flags.

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There is probably a break in L1 or L2 at a daisy chained jack. Down
stream of the break, there is no DC path for loop current to trigger
dial tone, BUT, since the ringer is AC, there can be a path back
through the ringer of a phone bridging the break [effectively two
phones in series] so the phone could ring, but not close the DC loop
when taken off hook.

Neil S.

EXCELLENT!

That would account for the electronic phone ringing very well,

Bet the old ATT 'dialer' phone has a weak ring, right?

 

[David Lesher]

Agree re: corroded wiring connection as likely cause.

Go to each jack and put a *milliammeter* across Tip-Ring.
Start at the demark.

You should see 20+ mA. If you don't, it's the wiring or jack.

As a next step, put the meter in series with a phone, and see if the off-hook
current is still >20mA.

The first indicts the upstream wiring; the 2nd is likely the phone.


--
A host is a host from coast to coast.................wb8foz@nrk.com
& 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

 

[Bill Janssen]

David Lesher wrote:

Agree re: corroded wiring connection as likely cause.

Go to each jack and put a *milliammeter* across Tip-Ring.
Start at the demark.

The milliampmeter should be in series with a 400 Ohm resister. The

resister represents the resistance
in the phone.

Bill K7NOM

You should see 20+ mA. If you don't, it's the wiring or jack.

As a next step, put the meter in series with a phone, and see if the off-hook
current is still >20mA.

The first indicts the upstream wiring; the 2nd is likely the phone.

 

[David Lesher]

Bill Janssen <billj@ieee.org> writes:

Agree re: corroded wiring connection as likely cause.

Go to each jack and put a *milliammeter* across Tip-Ring.
Start at the demark.

The milliampmeter should be in series with a 400 Ohm
resister. The resister represents the resistance in the phone.

Not needed at all, and misses the point. The phone is not a
fixed resistance; it's a small voltage drop that varies with
loop length.

The outside plant loop and the line relay at the CO limit the
current. Let's say you are 5000 ft from the CO; that's 250 ohms
right there. The line relay is say 500 ohms. Worst case, 60 odd
mA. In reality the line card will limit it to far less.

Nothing you can do to your end of the loop will damage anything.

Your goal is to see the max available current. If it's not
sufficient at a jack, but is at the demark; there must be a bad
splice in the IW. And measuring the voltage with a open circuit is
sorta pointless.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& 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