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Plantronics Discovery 640 Bluetooth Headset

By Adam Z. Lein February 1, 2006, 12:00 am



For years, Bluetooth
headset manufacturers have been innovating by trying
different ear mounting systems, getting better
sound, making them smaller/lighter, or adding other features
like caller ID. You can’t see an LCD display when
it’s hanging on your ear! Anyway, the Plantronics
Discovery 640 actually takes a different approach to
innovation and makes their high-end headset easier
to use, easier to recharge, and easier to carry
while retaining the other important things like
size, comfort, etc.
Read on to see exactly how they did this.



The Discovery 640 has a lot of exciting
features. The charging cradle can be modified to fit
your existing phone’s charging, thus reducing the
number of AC adapters you need to car. It can also
take a AAA battery for charging.

One of the biggest
problems with using a Bluetooth headset, is where do
you put it when you’re not using it? Other
manufacturers often provide a lanyard that you can
use to hang it around your neck, but that’s not very
good for when you want to put it in your ear. Others
have belt holsters or just assume you’ll keep it in
your pocket where it might bang against your keys or
whatnot. Ideally, the headset would slide out of your
phone so that you could keep the two together when
not in use as outlined in my

2003 PDA wishlist
. Well, the Discovery 640 comes
closest to that type of functionality with it’s
pen-like carrying case that can clip into any

Another problem with
Bluetooth headsets is that you usually have to have
it in your ear to tell if the phone’s ringing when
you’re phone is stored away in your bag or
something. When the Discovery 640 is in it’s
charging cradle, the whole thing vibrates
when a call is coming in. And unlike some other
headsets, when the Discovery 640 is in your ear
(i.e. not in the cradle) it does not vibrate.  Furthermore, and this is a great
feature I’m happy to finally see implemented, when
you take the headset out of the cradle, it
automatically answers the call. That’s right, no
longer do you have to press a button to answer
manually! Then with the headset’s non-obtrusive gel
earpieces, you just stick it in your ear as if it
were an ear-bud headset. No difficult
ear loop mounting systems to figure out! It’s even
easier than Nextlink’s ear mounting system!

Bluetooth Headset
Talk Time | Standby (hours)
Weight (grams | ounces)
St Price (as of 2/1/06)
Plantronics Discovery 640
15 | 300*
9.00 | 0.32
Movon MF200
5 | 150
15.0 | 0.53
Logitech Mobile Traveller
7 | 300
14.2 | 0.50
Southwing SH305
6 | 300
11.0 | 0.38
Gennum nXZEN Plus
7 | 100
17.0 | 0.54
5 | 250
20.0 | 0.71
2 | 100
5.85 | 0.21
Nextlink Bluespoon AX2
8 | 1000
10.0 | 0.35
Nextlink Bluespoon AX
4 | 200
12.0 | 0.42

*with use of AAA battery option. Click on any headset title above to see our review.



One of the most unique features of the
Plantronics Discovery 640 is its modular
cradle/charging design. The cradle that holds the
headset has a propietary connector on the bottom
where you can attach a variety of different charging
adapters designed to fit the existing charging
cables for most popular phone manufacturers. See the
diagram below for what’s included with the Discovery

1. Headset
2. Headset Status Indicator
3. Call Control Button (On/Off)
4. Volume/Mute Button
5. Headset Carrying Pocket
6. Battery Charger
7. Battery Holder
8. Battery (AAA)
Charging Adapters
10. Optional Ear Stabilizer
11. Soft Gel Ear Tip
a. Small
b. Medium
c. Large
12. Microphone
13. Storage Case
14. AC Power Adapter



First off, you have to make sure
the headset is charged up, and the Discovery 640 has many options for
that. The Headset Status Indicator glows red during charging and turns
off when fully charged. Then you can turn it on by pressing and holding
the call button for about 3 seconds. The status light should glow blue
when it’s on and will blink blue every 6 seconds. Holding the call
button down for about 6 seconds will turn it off (indicated by the red
status light). While powered on the status indicator will also indicate
battery level between blue flashes. Here’s how:


  • Greater than 2/3 battery charge
    = 3 red flashes.

  • 1/3 to 2/3 battery charge = 2
    red flashes.

  • Less than 1/3 battery charge = 1
    red flash.


     Then you’ve
got to pair the headset with your phone over
Bluetooth so that you can use it. I used my imate K-JAM Pocket PC Phone.
First shut the headset off, and then turn it back on
by holding the call button down. Once it turns on,
keep holding the button down until the status
indicator light starts flashing red and blue. This
means that it will be in pairing mode for about 30
seconds. Now
you can go to your Pocket PC Phone (or other
Bluetooth phone) and search for Bluetooth devices
within range. When the “640 Plantronics” shows up in the
list, you can initiate a pairing with it. The PIN
number to enter when requested is “0000”.
After a successful pairing, your headset will
be functional as a Handsfree or Headset device
depending on which Bluetooth profiles your phone
supports. Now any
calls I make from the imate K-JAM will be automatically sent to the
Discovery 640.




Discovery 640 has a simple 3
button interface. The larger call control button is
placed at an angle near at the upper end of the
headset. The angle helps keep the headset from
mashing against your ear when pressing the button.
The other two buttons handle volume up and down. Pressing
both volume buttons until you hear a beep toggles
the mute function.

    To answer a call, you
can either press any button or remove the headset
from it’s charging cradle. Pressing the call control
button once will end the call. You can invoke the
redial function by pressing the call control button
twice (you’ll hear a high pitched tone for each
press.) A long press of the call control button
(until you hear a lower pitch tone) will activate
voice dialing, or in the case of my K-JAM, Microsoft
Voice Command. Shutting off the voice dialing audio
gateway requires another press-and-hold of the call
control button.

    In addition to the
battery level features of the status indicator
mentioned earlier, there are a few other unique
features. When the phone is ringing, the status
indicator light will rapidly blink blue and red. If
you missed a call the indicator light will
periodically blink blue and red. Now that’s another
great feature!

    The Discovery 640 also
supports the Bluetooth 1.2 standard for faster
reconnecting times. The battery life should give you
about 5 hours of talk time, but if you use the AAA
charger cradle to store the headset when not in use,
you can get about 15 hours talk time (but not all at

(all images link to higher resolution)

Even with all the usability
features, the Plantronics also features an
acceptably small form-factor.

It’s still not as small as the
Nextlink Bluespoon 5G, but comes pretty close to the
Bluespoon AX. At 9 grams, it’s actually a bit
lighter than the 10g Bluespoon AX.

    When attached to its charging
cradle and AAA powered charger, the Discovery 640
looks like the memory erasing device from “Men in
Black.”  This configuration is about the size
of a highlighter marker. There’s a pen-like
clip on the other side that lets you easily store
this in a shirt pocket. And as mentioned before,
this whole set-up will vibrate when a call comes in.

The carrying case has form-fitted
areas for each of the Plantronics Discovery 640’s
parts (except for the AC adapter). The whole package
will easily fit in a jacket pocket. It looks like
some sort of futuristic weapon! Pretty cool.

There’s also a mirror on the back
of the case so you can check yourself out when
mounting the headset.

     We tested the Discovery 640 at the
Chinese New Year celebration in Chinatown New York
City. Due to the soft ear-gel and loud internal
speaker I was able to easily hear other callers who
were lost and swallowed up into the crowd. However,
the 640’s microphone did not fair too well in such a
noisy environment. I didn’t really expect it to,
since it doesn’t have any kind of noise reduction.
On the plus side, those ear-gels are very
comfortable. Even though the 640 weighs about 9
grams, it felt like I was wearing the Bluespoon 5G.
If it’s not sturdy enough for your ear, there’s an
optional ear stabilizer attachment as well.


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Plantronics Discovery 640 Bluetooth Headset

1 ,

Review by:
Adam Z Lein, Senior Editor

to: PAGE 1 |



Plantronics has some
really great support options on their

website. You can search their knowledge base,
submit a question via the web, or chat live with a
support technician. There’s even an Instant Live
Talk option where a support representative will call
you for free after you send them your phone number!
There’s also an easy form to fill out for warranty
repair and headset replacement.



You need a
Bluetooth enabled phone, PDA, or Computer with the Headset or Handsfree
profiles in order to use the Plantronics Discovery 640. It will work
with any Bluetooth version including Bluetooth 1.1, 1.2, and 2.0.  



The worst part of the Discovery 640 headset is that
the microphone occasionally performs very poorly.
It’s sometimes quite random as well. I could be on
the phone with one caller who could barely hear me
through the headset one day. Then another day with
the same caller, he would be able to hear me just
fine. Then of course there’s the inability of
callers to hear me talking at the Chinatown New
Years activities, but this headset doesn’t claim to
have any noise reduction capabilities.

The Discovery 640 is supposed to be able to play
your phone’s ringtone through the headset when an
incoming call is ringing. This unfortunately didn’t
work with my i-mate K-JAM, and thusly wouldn’t work
with Microsoft Voice Command’s verbal caller ID
announcements. This is probably more a problem with
Windows Mobile 5.0 than Plantronics’ implementation.

I really like the gel-ear-bud type mounting system.
However, even though it comes with 3 different
sizes, it may still not fit your ear perfectly. I’d
like to see a more malleable and ergonomic ear-bud
attachment in future versions. It should just pop-in
and stay attached. This type of mounting system
would also feel more secure if the headset lost some
weight. I’m sure future versions of the Discovery
headset will address this. Hopefully they’ll be able
to get the charging cradle down to the size of a
ball point pen cap as well.

What would be really nice is if they could make this
about 50% smaller, and have the docking sleeve built
into a Windows Mobile Phone or Pocket PC Phone. That
way you could keep both in the same pocket, use the
same charger, and just slide out the headset to
answer a call.




  • Modular
    charging cradle system
  • 9 grams
  • Vibrating
  • Very easy
    to use and comfortable mounting system
  • Battery
    level indicator
  • Missed
    call indicator



  • Outgoing
    audio can be poor at times
  • No noise
  • Mini-USB
    adapter sold separately
  • Charging cradle is not built
    into a Windows Mobile phone
of Use


do these ratings mean?



I was very excited when I learned about all the
great features this headset has. The
vibrating pen-clip holder/charger/cradle feature
alone may be worth upgrading to this headset. The
variety of adapters designed to fit other phone
manufacturer’s proprietary AC adapters is a
beautiful idea as well. Perhaps my random microphone
issues are an isolated result of a defective unit.
Regardless, this headset is so chock full of
well-implemented, innovative, and beautiful
engineering. It’s sure to influence the other
Bluetooth headset manufacturers in the future.

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