Why would a DECT Panasonic cordless phone keep losing the wirelesslink?

[Danny D'Amico]

Any idea why fully-charged DECT Panasonic cordless phones would
keep losing their wireless link lately?
http://farm4.staticflickr.com/3720/11812145904_ab84d957e3_o.gif

They're not at all far (fifteen feet) from the base and, this
loss of signal only started happening about a year ago (the phone
is probably about three or four years old).

So, something clearly aged (but the batteries show as fully charged
and I've changed them between handsets anyway).

The error I keep getting (on multiple handsets) is:
No Link. Reconnect base AC adapter.

This happens after, say, a few minutes of talking time, but, it's
erratic. Sometimes I can be on the line for an hour before it
happens; other times it happens within five minutes.

What frustrates me is the lack of debugging techniques.

Reconnecting the phone to the charger doesn't change anything;
nor does placing each of the handsets back into the mother phone
to reinitialize them.

Here's the DECT Panasonic KX-TG6441 phone & handsets:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

Here's the model number plate:
http://farm6.staticflickr.com/5539/11812098283_c1f2dc22f0_o.gif

Googling for that error message, I see it's pretty common; but
I already tried the little that Panasonic suggests:
http://eng-na.faq.panasonic.com/app...base.-reconnect-ac-adaptor.-what-should-i-do?

The outlet is working fine; the phone works fine from the base;
it's just the handsets that keep losing their wireless connection.

Anyone else resolve this problem before?
Any debugging hints?

 

[mike]

Any idea why fully-charged DECT Panasonic cordless phones would
keep losing their wireless link lately?
http://farm4.staticflickr.com/3720/11812145904_ab84d957e3_o.gif

They're not at all far (fifteen feet) from the base and, this
loss of signal only started happening about a year ago (the phone
is probably about three or four years old).

So, something clearly aged (but the batteries show as fully charged
and I've changed them between handsets anyway).

The error I keep getting (on multiple handsets) is:
No Link. Reconnect base AC adapter.

This happens after, say, a few minutes of talking time, but, it's
erratic. Sometimes I can be on the line for an hour before it
happens; other times it happens within five minutes.

What frustrates me is the lack of debugging techniques.

Reconnecting the phone to the charger doesn't change anything;
nor does placing each of the handsets back into the mother phone
to reinitialize them.

Here's the DECT Panasonic KX-TG6441 phone & handsets:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

Here's the model number plate:
http://farm6.staticflickr.com/5539/11812098283_c1f2dc22f0_o.gif

Googling for that error message, I see it's pretty common; but
I already tried the little that Panasonic suggests:
http://eng-na.faq.panasonic.com/app...base.-reconnect-ac-adaptor.-what-should-i-do?

The outlet is working fine; the phone works fine from the base;
it's just the handsets that keep losing their wireless connection.

Anyone else resolve this problem before?
Any debugging hints?

Sounds like interference.

I recently switched to a high-power router and Wi-Max wireless internet.
One or both drove my 2.4GHZ wireless phone crazy. Hardly worked at all,
even up close.
I powered up the spectrum analyzer. Yep they were right on top of
one another.
I switched to a DECT phone, which, as I recall, works on different
frequencies.
Problem got a lot better. I still can't stand too close to the router.

 

[Danny D'Amico]

Have you added anything like a wireless router for the internet ? Sometimes
phones and other wireless devices will interfear with other.

Yes. There is lots of WiFi in the house.

There are also other cordless bases and phones on other lines, e.g.,
http://farm3.staticflickr.com/2873/11811729095_cafdd2467b_o.gif

For example, this Panasonic KX-TG6671 seems to work just fine though:
http://farm3.staticflickr.com/2806/11812266724_b252b01faf_o.gif

 

[Danny D'Amico]

Since it happens with multiple handsets, it's a fair assumption that
all of the handsets did not simultaneously fail. Therefore, whatever
is wrong is at the base unit.

Hi Jeff,

Googling, it says the error indicates the base station loses its
power, but, that's just not happening, at least not from a loose power
cord.

The reason I know that's not happening, other than it's not, is that
not all of the handsets fail at any one time. Only one handset fails
at a time.

So, if it was the base failing (which is what the error indicates),
then all the handsets should fail simultaneously, I would think.

 

[Danny D'Amico]

Clue. The transmit power of the base is only about 10 mw of RF. It
doesn't take much to ruin that.

As someone suggested, I guess it could be my 2.4GHz WiFi antenna
that is causing problems; but why would that be intermittent?

I suggest you open up the base unit, and see if there's anything amiss

This is likely. The error indicates a lack of power at the base,
but, there isn't any overt lack of power at the base.

if it uses the same charger as the remote chargers, try swapping
the charger.

This makes a lot of sense - and it's a good idea, especially since the
error indicates a lack of power at the base.

I'll try that and re-test & report back.

 

[Danny D'Amico]

Sounds like interference.

It could be. There's a lot of WiFi floating around my house these days.

I recently switched to a high-power router and Wi-Max wireless internet.

I had to look up WiMax:
http://en.wikipedia.org/wiki/WiMAX

I powered up the spectrum analyzer.
Yep they were right on top of one another.

I hadn't thought of aiming my spectrum analyzer inside (mine is pointed
outside). What I may try is setting up a spectrum analysis where I
run a 1000 frames without any devices plugged in, and then another
1000 frames with all my WiFi devices plugged in to see if there is a
big difference.

I switched to a DECT phone, which, as I recall, works on different
frequencies.

I don't know what frequency DECT works on, but, two of my four
phone bases are DECT.

 

[Tony Hwang]

Any idea why fully-charged DECT Panasonic cordless phones would keep
losing their wireless link lately?
http://farm4.staticflickr.com/3720/11812145904_ab84d957e3_o.gif

They're not at all far (fifteen feet) from the base and, this loss of
signal only started happening about a year ago (the phone is probably
about three or four years old).

So, something clearly aged (but the batteries show as fully charged
and I've changed them between handsets anyway).

The error I keep getting (on multiple handsets) is: No Link.
Reconnect base AC adapter.

This happens after, say, a few minutes of talking time, but, it's
erratic. Sometimes I can be on the line for an hour before it
happens; other times it happens within five minutes.

What frustrates me is the lack of debugging techniques.

Reconnecting the phone to the charger doesn't change anything; nor
does placing each of the handsets back into the mother phone to
reinitialize them.

Here's the DECT Panasonic KX-TG6441 phone & handsets:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

Here's the model number plate:
http://farm6.staticflickr.com/5539/11812098283_c1f2dc22f0_o.gif

Googling for that error message, I see it's pretty common; but I
already tried the little that Panasonic suggests:
http://eng-na.faq.panasonic.com/app...base.-reconnect-ac-adaptor.-what-should-i-do?

The outlet is working fine; the phone works fine from the base; it's
just the handsets that keep losing their wireless connection.

Anyone else resolve this problem before? Any debugging hints?

Hi
One base and many handsets? Then logic tells me radio in the base unit
is suspect. Or turn all handsets but one and try. By any chance checked
the wall wart for the base unit? We have multi handsets but they are
divided between two different base units. If some thing goes wrong easy
to trouble-shoot

 

[Danny D'Amico]

whatever is wrong is at the base unit.

This is a good observation.

I picked up the Panasonic KX-TG6441 "Operating Instructions":
http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

And the "Installation Manual" for the Panasonic KX-TG6441:
http://service.us.panasonic.com/OPERMANPDF/KXTGA740B.PDF

The frequency range is *below* the 2.4GHz WiFi range:
Frequency Range = 1.92 GHz to 1.93 GHz

And the claimed RF Transmission power is 115 mW (max.).

 

[Geoffrey S. Mendelson]

I recently switched to a high-power router and Wi-Max wireless internet.
One or both drove my 2.4GHZ wireless phone crazy. Hardly worked at all,
even up close.
I powered up the spectrum analyzer. Yep they were right on top of
one another.
I switched to a DECT phone, which, as I recall, works on different
frequencies.
Problem got a lot better. I still can't stand too close to the router.

There are three kinds of interference that can happen in this case.

The first is direct interference, where your WiFi unit operates on 2.4gHz
and your cordless phone also operates on 2.4gHz. The old 2.4gHz phones
did not listen for activity on a channel before transmitting on it, and
often would wipe out Wifi.

The newer DCT phones listen, but there is only so many channels and eventually
they overlap.

Since 2.4gHz is 1/2 of 5.8 gHz, the second harmonic of WiFi can interfere
directly with 5.8gHz phones and so on.

The second is intermodulation, where two signals combine and the difference
or sum causes interference. Not likey in this case.

The third is desensitization, where a strong signal on a relatively near
frequency overloads the receiver in a device. So a WifI router can cause
DECT phones to stop receiving, even though WiFi is 2.4gHz and DECT is 1.7gHz.

That's why you can't talk on the DECT phone near your WiFi device.

It's very likely that the OP is experienceing desensitazation or direct
interfernce.

Another thing they can try is to move the base station. Especially if it
is sitting next to another wireless device.

Geoff.

 

[Geoffrey S. Mendelson]

As someone suggested, I guess it could be my 2.4GHz WiFi antenna
that is causing problems; but why would that be intermittent?

It may not be YOUR WiFi that is causing it. Unless you live in a single
family house about 1/2 km from anyone else and a road, you could have
problems with interference from other WiFi devices, cordless phones,
cell phones, and so on.

I live in a steel and poured concrete building, and away from the center of
it (I'm on a middle floor), say my bedroom, I can only "hear" my Wifi.
In my living room which is in the center, I can "hear" 8 unprotected
WiFi networks, and a few protected ones. It's a miracle I can use my
WiFi there.

Geoff.

 

[Phil Allison]

"Geoffrey S. Mendelson"

Since 2.4gHz is 1/2 of 5.8 gHz,

** That some new kind of math ???

ROTFL



.... Phil

 

[William Sommerwerck]

You're spending too much time analyzing the problem, and not enough time
testing.

Why hasn't someone suggested changing the WiFi channel? That's a great place
to start testing.

 

[John Grabowski]

Any idea why fully-charged DECT Panasonic cordless phones would

keep losing their wireless link lately?
http://farm4.staticflickr.com/3720/11812145904_ab84d957e3_o.gif

They're not at all far (fifteen feet) from the base and, this
loss of signal only started happening about a year ago (the phone
is probably about three or four years old).

So, something clearly aged (but the batteries show as fully charged
and I've changed them between handsets anyway).

The error I keep getting (on multiple handsets) is:
No Link. Reconnect base AC adapter.

This happens after, say, a few minutes of talking time, but, it's
erratic. Sometimes I can be on the line for an hour before it
happens; other times it happens within five minutes.

What frustrates me is the lack of debugging techniques.

Reconnecting the phone to the charger doesn't change anything;
nor does placing each of the handsets back into the mother phone
to reinitialize them.

Here's the DECT Panasonic KX-TG6441 phone & handsets:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

Here's the model number plate:
http://farm6.staticflickr.com/5539/11812098283_c1f2dc22f0_o.gif

Googling for that error message, I see it's pretty common; but
I already tried the little that Panasonic suggests:
http://eng-na.faq.panasonic.com/app...base.-reconnect-ac-adaptor.-what-should-i-do?

The outlet is working fine; the phone works fine from the base;
it's just the handsets that keep losing their wireless connection.

Anyone else resolve this problem before?
Any debugging hints?

*The last time my Panasonic phone did that, I replaced the batteries with
new ones. Problem went away. If yours are four years old I would think
that it is time for a battery replacement. Home Depot has them and I think
Wal-Mart does also.

 

[Jeff Urban]

If they're 2.4 Ghz, wifi could be interfering too much.

 

[Percival P. Cassidy]

Yes. There is lots of WiFi in the house.

There are also other cordless bases and phones on other lines, e.g.,
http://farm3.staticflickr.com/2873/11811729095_cafdd2467b_o.gif

For example, this Panasonic KX-TG6671 seems to work just fine though:
http://farm3.staticflickr.com/2806/11812266724_b252b01faf_o.gif

Our Panasonic DECT phones are on 1.9GHz, I'm almost certain -- not on
the common 2.4GHz WiFi frequency.

Perce

 

[Geoffrey S. Mendelson]

Our Panasonic DECT phones are on 1.9GHz, I'm almost certain -- not on
the common 2.4GHz WiFi frequency.

DECT phones are on 1.9gHz (1.7 in Europe), DCT phones at 2.4gHz.

They are similar, and of course, incompatible.

Geoff.

 

[Oren]

Why hasn't someone suggested changing the WiFi channel?

I was thinking about it

That's a great place to start testing.

Even suggested when installing a home router. Change the channel if
there are problems.

 

[Danny D'Amico]

There are three kinds of interference that can happen in this case.
The first is direct interference
The second is intermodulation
The third is desensitization, where a strong signal on a relatively near
frequency overloads the receiver in a device. So a WifI router can cause
DECT phones to stop receiving, even though WiFi is 2.4gHz and DECT is 1.7gHz.

This is very useful information, an applicable to the WiFi group as well.

My DECT Panasonic KX-TG6441 phones & handsets apparently operate at
1.9 GHz, according to page 6 of this PDF:
http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF
"The product operates in the frequency range of 1.92 GHz to 1.93 GHz,
and the RF transmission power is 115 mW (max.)"

 

[Danny D'Amico]

Our Panasonic DECT phones are on 1.9GHz, I'm almost certain -- not on
the common 2.4GHz WiFi frequency.

My problematic Panasonic KX-TG6441 cordless phone is also on 1.9 GHz,
as described on page 6 of this PDF:
http://farm4.staticflickr.com/3786/11829460325_b34ca30a30_o.png
http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

 

[Danny D'Amico]

Nope. If it's a loose antenna connection on the base, the handsets
close enough to get a minimal signal from the base would still work,
while those far away would loose the signal.

This is a good point!