Headsets for cordless phones

[Lloyd Randall]

A week ago I received a GE cordless phone and a Plantronics M110 headset
which I had ordered by the internet.

The phone has better range and clarity than my old one, and the headset
sounded great on my first conversation. Since then, I have discovered
that for most conversations the headset is not as good as listening to
the phone itself.

It sounds like an impedance mismatch. The input impedance for the M110
is 32 ohms, but GE doesn't seem to publish the output impedance for the
phone.

The Plantronics box says the headset is for mobile and cordless phones
and will provide crystal clear conversations for most headset-ready
phones. When I contacted them, they said the M series is not
recommended for 2.4GHz or DSS phones. Doesn't at least one of these
apply to most headset-ready cordless phones?

They recommend their H51N with an adaptor cord. I paid $20 for My M110,
while the H51N lists for $100, and I'd still have to find an adaptor.

I wanted a headset to make calls when I'm likely to be put on hold and
for incoming calls when I'd like to continue manual tasks. It would be
worth $20 to me but not $120. It would have saved me some trouble if
their advertising hadn't led me to believe they recommended the M110 for
my phone.

Besides price, the difference between the two headsets seems to be
impedance or the earphone. I think the H51N is 150 to 300 ohms, but I
haven't seen it published.

There's probably a suitable headset available for less than the H51N,
but vendors of cordless phones and vendors of headsets tend not to
mention impedance. How can a consumer match the two without knowing
impedance?

If I can't get specs for headsets, I might get specs for microspeakers,
to replace the one that came in the M110. For example, I've seen a
100-ohm microspeaker advertised for $2.

What should I do?

 

[Clifton T. Sharp Jr.]

It sounds like an impedance mismatch. The input impedance for the M110
is 32 ohms, but GE doesn't seem to publish the output impedance for the
phone.

The last GE phone I bought came with its own headset; it was 150 ohms.
I suspect your phone might be as well. Natch, no headset worked with my
phone when the supplied headset broke; VERY low earpiece volume.

 

[Lloyd Randall]

The last GE phone I bought came with its own headset; it was 150 ohms.
I suspect your phone might be as well. Natch, no headset worked with my
phone when the supplied headset broke; VERY low earpiece volume.

If a earphone were a resistive load, it would simply be too soft if the
source impedance were too high. In fact, earphones have mechanical
resonance at various frequencies. The higher the source impedance, the
louder these frequencies will sound, relative to other frequencies. The
output will wound harsh and distorted, and it will sound unclear because
some frequencies will be very soft.

With the GE phone, my M110 is harsh and unclear with some voices. I
think those are the voices that are strong in the frequencies where the
earphone resonates.

Telephone-line impedance is nominally 600 ohms. That would explain why
telephone headphones use to be at least 150 ohms. Earphones for
lightweight aviation headsets are nominally 600 ohms.

I think the walkman was responsible for the popularity of 32-ohm
earphones; with two penlight cells for a power supply, you couldn't get
loud music if the earphone impedance were much higher.

Is 32 ohms standard for cellphone headphones? If so, it may be because
walkman earphone elements were readily avialable. If cordless phones
don't use the same headphone impedance, could it be because
manufacturers don't want customers buying cheap cellphone headphones for
their cordless phones?

There must be inexpensive 150-ohm headsets or earphone elements
available. If only specs were easier to find!

 

[Clifton T. Sharp Jr.]

If a earphone were a resistive load, it would simply be too soft if the
source impedance were too high. In fact, earphones have mechanical
resonance at various frequencies. The higher the source impedance, the
louder these frequencies will sound, relative to other frequencies. The
output will wound harsh and distorted, and it will sound unclear because
some frequencies will be very soft.

I have loud tinnitus; the volume was too low for me to detect distortion.
It was low enough that I could barely detect speech, and too low to hear
what was being said.

With the GE phone, my M110 is harsh and unclear with some voices. I
think those are the voices that are strong in the frequencies where the
earphone resonates.

That argues in favor of yours being high-impedance as mine was.

Telephone-line impedance is nominally 600 ohms. That would explain why
telephone headphones use to be at least 150 ohms. Earphones for
lightweight aviation headsets are nominally 600 ohms.

But that doesn't say a thing about why GE picked a nonstandard speaker
impedance for installation in their entirely electronic cordless phone.
All the other cordless phones I've had worked fine with a 32-ohm headset,
even one 8-ohm headset.

There must be inexpensive 150-ohm headsets or earphone elements
available. If only specs were easier to find!

Simpler is to get another phone. I'm so spoiled by the headset that I
can't hold an earpiece any more.

I bought a V-tech branded Radio Shack because it showed up $100 off and
was nice and small. Dropped it once too often, replaced it with another
RS unit made by Uniden that's both inexpensive and really nice, still
on sale at RS.

 

[Lloyd Randall]

I have loud tinnitus; the volume was too low for me to detect distortion.
It was low enough that I could barely detect speech, and too low to hear
what was being said.

I hear you! The phone I replaced was another GE cordless. It had
become so faint that I'd shut off all noise sources and jam the phone
hard against my ear, but I'd still have trouble understanding what was
said. Even if all phones had microphones with the same gain, some
voices would be faint because people let the mike get too far from their
mouth. Some of the faintest are in customer service.

The first time I tried my headset, I walked around outdoors to see the
range of the cordless phone. The man I was talking to said he knew I
was near the limit of the phone's range because he kept hearing pulses
of hissing as I moved around. I never heard them until I tried the
phone without the headset. I guess the impedance mismatch made those
frequencies too faint to hear in the headset.

Overall, my headset sounded reasonably loud (but not clear and pleasant)
because resonance made the impedance high at some frequencies.

But that doesn't say a thing about why GE picked a nonstandard speaker
impedance for installation in their entirely electronic cordless phone.
All the other cordless phones I've had worked fine with a 32-ohm headset,
even one 8-ohm headset.

Hmmmm... how long have headset-ready cordless phones been available?
Did any of your phones operate at 2.4 GHz or have DSS? Plantronics says
they don't recommend their 32-ohm headsets for any of these phones. It
sounds as if a lot of manufacturers are using higher impedances.

Simpler is to get another phone. I'm so spoiled by the headset that I
can't hold an earpiece any more.

According to Plantronics, buying another phone may not solve the problem.

I bought a V-tech branded Radio Shack because it showed up $100 off and
was nice and small. Dropped it once too often, replaced it with another
RS unit made by Uniden that's both inexpensive and really nice, still
on sale at RS.

My cordless phone/answering machine cost $30. GE has a headset for $35,
but I'd rather do without than buy theirs, under the circumstances.
When they said "headset ready," didn't they imply that a standard mobile
headset would work?

I'll watch for a suitable headset or microspeaker.

 

[sg]

Did your GE phone list which headsets would work with it? If not, you
might try posting your question on a newsgroup slanted toward cordless
phones or electronics, asking if anyone has the model phone you have
and is using a headset. You might get some good replies.

Good luck.

 

[Andrew White]

A week ago I received a GE cordless phone and a Plantronics M110 headset
which I had ordered by the internet.

The phone has better range and clarity than my old one, and the headset
sounded great on my first conversation. Since then, I have discovered
that for most conversations the headset is not as good as listening to
the phone itself.

It sounds like an impedance mismatch. The input impedance for the M110
is 32 ohms, but GE doesn't seem to publish the output impedance for the
phone.

The Plantronics box says the headset is for mobile and cordless phones
and will provide crystal clear conversations for most headset-ready
phones. When I contacted them, they said the M series is not
recommended for 2.4GHz or DSS phones. Doesn't at least one of these
apply to most headset-ready cordless phones?

They recommend their H51N with an adaptor cord. I paid $20 for My M110,
while the H51N lists for $100, and I'd still have to find an adaptor.

I wanted a headset to make calls when I'm likely to be put on hold and
for incoming calls when I'd like to continue manual tasks. It would be
worth $20 to me but not $120. It would have saved me some trouble if
their advertising hadn't led me to believe they recommended the M110 for
my phone.

Besides price, the difference between the two headsets seems to be
impedance or the earphone. I think the H51N is 150 to 300 ohms, but I
haven't seen it published.

There's probably a suitable headset available for less than the H51N,
but vendors of cordless phones and vendors of headsets tend not to
mention impedance. How can a consumer match the two without knowing
impedance?

If I can't get specs for headsets, I might get specs for microspeakers,
to replace the one that came in the M110. For example, I've seen a
100-ohm microspeaker advertised for $2.

What should I do?

You're getting very technical, but I doubt you found the right reason.
The headset might just be junky. I tried a whole bunch of different
ones until I found a perfect one that sounded great: Panasonic
KX-TCA88. They are cheap too, under $25.

 

[Lloyd Randall]

Did your GE phone list which headsets would work with it? If not, you
might try posting your question on a newsgroup slanted toward cordless
phones or electronics, asking if anyone has the model phone you have
and is using a headset. You might get some good replies.

Good luck.

I looked first for telephone newsgroups. I found three for cell phones
and none for cordless.

I crossposted. I figured somebody at electronics.repair might have
technical information.

It also seems to be a consumer issue. Cordless phones are very popular,
and many are headset ready these days. The phone box said it was
headset-ready, and the headset box said it was for most headset-ready
phones.

Only when I opened the phone box and read the manual did I learn that GE
recommended only their headset accessory, which would cost me twice what
I paid for the Plantronics headset. After I found that the Plantronics
headset did not work satisfactorily with this phone, Plantronics told me
they in fact do not recommend this headset for two categories which
probably comprise most headset-ready cordless phones sold today.

The same pitfall awaits any consumer in the market for a headset for a
cordless phone.

Instead of spending over $100 for the headset Plantronics recommends, I
can buy hundred-ohm cellphone speakers for 50 cents. One of those would
be small enough to replace the speaker in my headset.

I think I see why many new cordless phones seem to be designed for
higher-impedance headsets than used to be standard. It probably
increases the amount of time a consumer can talk between charges. I
just wish manufacturers would put impedance requirements on their
packages.

 

[Clifton T. Sharp Jr.]

Hmmmm... how long have headset-ready cordless phones been available?
Did any of your phones operate at 2.4 GHz or have DSS? Plantronics says
they don't recommend their 32-ohm headsets for any of these phones. It
sounds as if a lot of manufacturers are using higher impedances.

The V-tech and the current RS/Uniden were both 2.4GHz and DSS. Plantronics'
headset gives *me* good volume with them, but their boom mike gives low
outgoing volume on those two and two other phones I tried it on. (Works
fine with the cell phone, though.) I currently use a $30 RS binaural
headset with the RS/Uniden phones and like it.

 

[Lloyd Randall]

The V-tech and the current RS/Uniden were both 2.4GHz and DSS. Plantronics'
headset gives *me* good volume with them, but their boom mike gives low
outgoing volume on those two and two other phones I tried it on. (Works
fine with the cell phone, though.) I currently use a $30 RS binaural
headset with the RS/Uniden phones and like it.

Oh no! I have to worry about the mike, too? Plantronics gave the M110
a three-position switch so the user could choose -45, -50, or -55 db.
You can't please everyone. One caller preferred -45 and another -55, so
I leave the switch at -50.

Any equipment you plug into the line input of a stereo amplifier should
work because it's all supposed to have a signal of 1 volt and an
impedance of 600 ohms. Phonograph signals also have electrical
specifications, allowing one to use different turntables or cartridges.

Telephone equipment used to adhere to electrical specifications. Aren't
there electrical standards for the signals at the headset jack of a
phone? What a mess!

You've gotten me curious about Uniden/RS.

 

[Lloyd Randall]

You're getting very technical, but I doubt you found the right reason.
The headset might just be junky. I tried a whole bunch of different
ones until I found a perfect one that sounded great: Panasonic
KX-TCA88. They are cheap too, under $25.

I don't think my Plantronics is junky, but it could be that Panasonic
has done a better job designing a headset to work with a phone like mine.

The KX-TCA88 doesn't seem to be available any longer, and I don't know
if newer models are as cheap. Panasonic headsets have pleased owners of
some 2.4 GHz phones. I wish I knew if that means they would excel on
all 2.4 GHz phones.

 

[killme]

I've been trying to find a headset to work with my Uniden phone. I've
tried 4 headsets. On 3 of them the caller can barely hear me. All of
them had the mic positioned some distance from my mouth. The one that
worked had the mic positioned very close to my mouth, but it was over
the head design and I can't stand wearing it.

The first two I tried worked great on my friend's cell phone and were
designed for his headphone. The third was designed for cordless phones
according to the package. I just don't get it.

 

[[email protected]]

I've been trying to find a headset to work with my Uniden phone. I've
tried 4 headsets. On 3 of them the caller can barely hear me. All of
them had the mic positioned some distance from my mouth. The one that
worked had the mic positioned very close to my mouth, but it was over
the head design and I can't stand wearing it.

The first two I tried worked great on my friend's cell phone and were
designed for his headphone. The third was designed for cordless phones
according to the package. I just don't get it.

The only one I've found that works was ~$20 from Radio Shack, but it's
an over the head design, too. We tried those relatively expensive tiny
headsets but callers just couldn't hear us, no matter how we positioned
the short microphone. Even the one that works must be adjusted so that
the foam-covered boom mike is nearly directly in front of the mouth.

The headset hassle got to the point where we just talk on the phone
without it most of the time.

 

[Andrew White]

I've been trying to find a headset to work with my Uniden phone. I've
tried 4 headsets. On 3 of them the caller can barely hear me. All of
them had the mic positioned some distance from my mouth. The one that
worked had the mic positioned very close to my mouth, but it was over
the head design and I can't stand wearing it.

The first two I tried worked great on my friend's cell phone and were
designed for his headphone. The third was designed for cordless phones
according to the package. I just don't get it.

The best headset I've found after trying maybe as many as 7-8 headsets
from various companies was Panasonic KX-TCA88. The sound quality is
amazing, comfort is great and it's only $20. It's been replaced by
other models, but you can still find it on the Web, for example:
http://www.xkms.org/Etronics-35/Pan...eight-Headset-for-2.4-GHz-Cordless-Phones.htm

Here's the place that sells other, current Panasonic models. The TCA86
and TCA92 look similar, the latter has its own volume control:

http://www.101phones.com/browse/1d2710dd65d5039a1a04bf6ec85aacbd