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

[Danny D'Amico]

One base and many handsets?
Then logic tells me radio in the base unit is suspect.

This makes sense.

What I did today was I pulled the batteries out of the five handsets
and pulled the power from the base, and let it sit that way all day.
http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

Then, I performed the re-registration procedure as outlined on p27
of this PDF:
http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

Here's just the Panasonic cordless phone re-registration procedure:
http://farm8.staticflickr.com/7353/11829263895_ac761cd5cf_o.gif

Hopefully, re-registering all five handsets may help with the
problem of the Panasonic KX-TG6441 dropping calls after a while:
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

I'll let you know what happens...

 

[Danny D'Amico]

*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.

This might actually be the problem!

After removing all the batteries and allowing the handsets and base to sit
for about five hours today ...
http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

When I put the batteries back, I noticed that all five handsets said to
"Charge for 7 Hours" ...
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

So, I put them all on a 3.5 hour charger:
http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

And, when I put them back into the phone, they *still* said to
charge for 7 hours!
http://farm4.staticflickr.com/3756/11830061806_447da87566_o.gif

So, maybe it's that simple - that the Ni-MH batteries, which are a
few years old, are bad.

One problem though, is that I put the new Ni-MH batteries that came
with the charger in, after charging them on the charger, and the
handsets *still* said to charge for 7 hours.

So, something fishy is going on ... with the charge message on the
handsets ... but I don't know what yet.

 

[Danny D'Amico]

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

They're on 1.9 GHz ...
http://farm4.staticflickr.com/3786/11829460325_b34ca30a30_o.png

 

[Danny D'Amico]

In the USA, there's no GAP support, which means that phones from
different manufactories not only will not talk with each other, but
also can interfere with each other. You might try your problem phone
with the other DECT phones and base turned off.

That's a great suggestion Jeff.

Maybe these other DECT phones in the same house:
http://farm3.staticflickr.com/2873/11811729095_cafdd2467b_o.gif
Are causing the problem with this DECT phone:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

It might also be the batteries, although you can see in the previous
photo that they are fully charged - yet - I charged them today off
the Panasonic base:
http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

And, strangely, when I ran the registration procedure, they showed
up as being discharged! ?????????
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

So that makes absolutely no sense. I chalk it up to "confused
electronics" at this point - because I can't imagine what happened
to make a fully charged battery indicate almost discharged.

Anyway, as a precaution, I ran the re-registration procedure,
which is described on page 27 of this PDF:
http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

This is a snapshot of the re-registration procedure:
http://farm8.staticflickr.com/7353/11829263895_ac761cd5cf_o.gif

Since the menus don't show up until *after* you run the procedure,
I post below sequential screenshots so others who run the registration
procedure can see the cause and effect on the phones:

Press LOCATOR on base 4 sec. Then press OK.
http://farm4.staticflickr.com/3708/11829267845_c9363aba09_o.gif
Call from Base:
http://farm8.staticflickr.com/7392/11829686934_e1799e3098_o.gif
Base regtr'ing
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

 

[mike]

This might actually be the problem!

After removing all the batteries and allowing the handsets and base to sit
for about five hours today ...
http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

When I put the batteries back, I noticed that all five handsets said to
"Charge for 7 Hours" ...
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

So, I put them all on a 3.5 hour charger:
http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

And, when I put them back into the phone, they *still* said to
charge for 7 hours!
http://farm4.staticflickr.com/3756/11830061806_447da87566_o.gif

So, maybe it's that simple - that the Ni-MH batteries, which are a
few years old, are bad.

One problem though, is that I put the new Ni-MH batteries that came
with the charger in, after charging them on the charger, and the
handsets *still* said to charge for 7 hours.

So, something fishy is going on ... with the charge message on the
handsets ... but I don't know what yet.

Since about zero percent of people are gonna do that, they might have
concluded that a timer inside the device would determine
that the device had charged all it could and the display was in
terms of "do this" instead of any actual measurement, and be adequate to
direct 99.9999% of users to perform the operation.

Some people are "overthinkers" ;-)
Hmmm...I resemble that remark.

 

[Danny D'Amico]

Since about zero percent of people are gonna do that, they might have
concluded that a timer inside the device would determine
that the device had charged all it could and the display was in
terms of "do this" instead of any actual measurement, and be adequate to
direct 99.9999% of users to perform the operation.

That might be the case Mike, because I know two things.

The batteries were showing fully charged initially:
http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

Then, I removed them and let the phone sit for a few hours:
http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

When I then ran my first re-registration procedure, I was surprised
to see that all five phones suddenly showed low battery indications:
http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

That made no sense because pulling the batteries and letting them
sit disconnected for a few hours couldn't possibly have discharged
them from full to near zero. But it was easy enough to charge them
independently on a Ni-MH charger:
http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

Yet, I was again very surprised to see, after 3.5 hours on the
charger (the lights stop blinking on the charger to indicate full
charge) that, back in the handsets, they *still* said they were
low on charge!
http://farm4.staticflickr.com/3756/11830061806_447da87566_o.gif

Something doesn't add up - but all five handsets acted the same
way, even with the four new batteries from the charger put into
two of the handsets.

All five phones are now in their respective holders, and, I just
checked the charge, and they went from one bar to three bars, so,
that's just weird.

It's almost as if they'll only charge from their Panasonic
holders, and not from a separate non-Panasonic charger. But,
that makes no sense - so - I really don't know what to make of
this inconsistent data other than to ignore it.

 

[William Sommerwerck]

Don't you have a voltmeter? You shouldn't be depending on the base to inform
you as to whether the batteries are actually being fully recharged.

 

[Geoffrey S. Mendelson]

Two independent but incompatible DECT systems, on
the same frequency, are going to cause mutual interference. The
reason the problem is intermittent is that both bases have be on the
same channel in order to cause mutual interference. With 5 (US)
channels to use, you're chances are 1 in 5 of having a collision.
Unplug one base and see if the probleem goes away.

Part of the DECT standard is that a device listens before it transmits. If the
channel is in use, it changes the channel. What happens when all channels are
busy I have no idea.

What you describe was the problem with the old 2.4gHz cordless phones. They
just picked a channel and transmitted on it. The later ones were spread
spectrum, so as far as WiFi was concerned, it interfered on ALL of channels.

Or in plain English, when my upstairs neighbor's phone rang, my WiFi
crashed.

DCT phones work the same way as DECT phones, but on the 2.4gHz or 5.8gHz
band. Again, what they do when all channels are busy I do not know.

This is also why cell phones do not need to be licensed. They only
transmit when asked to by a cell, which in most places is licensed.

If for example, you were to bring a 1900mHz GSM phone to Europe, or a
900/1800mHz EU GSM phone to the US, it won't start transmitting and
interfere with whatever is using those frequencies.


Geoff.

 

[Danny D'Amico]

Don't you have a voltmeter? You shouldn't be depending on the base to inform
you as to whether the batteries are actually being fully recharged.

I was remiss in not mentioning that I tested the voltage with my fluke
but the problem, as always, with testing open circuit no-load voltage
is that without a load, a battery that tests good isn't necessarily good.

However, all the handsets are now reading full bars in battery voltage,
so, I'm inclined to assume that the battery-charge indicator on the
handsets isn't really a voltage indicator - but some sort of integrator.

The good news is that it hasn't happened since re-registration; but I also
haven't been on the phone a lot either. I will report back in a few days
to let you know if the problem is solved by the re-registration or not.

 

[Danny D'Amico]

Ummm... was the phone designed to use NiMH or NiCd batteries? I'm too
lazy to check.

Hi Jeff,
The batteries are the original, and, they're all Ni-MH batteries.
I noticed a set (white paint) was of a different amperage, so,
I reassembled all the sets with like-amperage batteries (to
prevent reverse voltage situations).

NiMH batteries can be a problem due to high self discharge and
possible overcharging. I suggest that you charge a few of the
batteries in the phones for a day and then remove the batteries.
Measure the voltage which should be about 1.2V when fully charged.
Just let them sit outside the handset for at least 12 hrs (or more).
Then measure the voltage again. 1.1V to 1.2V is fairly normal. 1.0V
is borderline.

I ran that from yesterday, Jeff, and they came back at 1.2 volts.
So, I must tentatively conclude that the phone itself has a
summative charging icon, where it might be "timed" in the charger,
rather than checked at the battery.

All five handsets, with the same batteries that read nearly dead
after charging, now read full. I haven't extensively tested yet,
but, all seems well now (tentative assessment).

With 5 (US) channels to use, you're chances are 1 in 5 of having
a collision. Unplug one base and see if the probleem goes away.

This might be the reason for the intermittence!

What I *should* do is buy a DECT system with 9 handsets instead
of two DECT systems for a total of 9 handsets.