Plantronics latest addition to the Bluetooth speakerphone market is the K100. The K100 is a slim, low profile speaker that slides on to your car's sun visor to allow hands free operation of your Windows Phone.

Not everyone is comfortable with a Bluetooth headset and the K100 gives drivers a hands-free alternative. Additionally, the K100 provides an FM transmitter that allows you to stream audio files from your Windows Phone through your car stereo.

To see if the K100 is worth the investment, make the jump past the break.


The K100 has a simple design, measuring 4.8 x 9 x 2.3 inches and weighing only 92 grams. It has three buttons on the surface (FM Transmitter, Multi-function and Mute) and a rotary dial that controls the volume. Twin microphones are placed at the top of the K100 with a healthy speaker taking up the bottom half of the speakerphone's surface.

A indicator light is positioned above the volume wheel to confirm actions and to alert users of various features. To the side is the micro-USB port to charge the K100's battery. The speakerphone is packaged with a user's guide and car charger.The K100 fits nicely on the sun visor, taking up very little real estate.


The K100 is basically an introductory level speakerphone with the basic feature set.  Most all are controlled with the center multi-function button through a series of touches, taps and holds. To power up the speakerphone, you press and hold the mult-function button. To redial, you double tap the multi-function button.

Other features include: Call Mute, FM transmission, voice dialing (phone dependent). You can put the device into Night Mode by pressing and holding the Mute Button and the indicator light will be disabled.

The FM Button, once pushed, will prompt an audio command as to which FM Station the transmission will play through.  The K100 is programmed to feed through five FM channels.  You can stream audio files and calls through your car stereo. This featured worked well with audio files playing nicely through your stereo.  I'm not sure of the need to stream calls through your car stereo with such a strong speaker on the K100.

The K100 is als programmed with various voice prompts that will confirm various features such as power on/off, pairing, battery low alerts, and call terminated. The K100 lacks any Caller ID functionality. 


The K100's performance is a mixed bag. The speaker volume is outstanding. Microphone performance is also outstanding. The noise reduction software and dual microphones cancel a significant amount of background noise. Everything from car noise to your car stereo becomes but a whisper in the background.

The K100's performance suffers in two areas; audio alerts and the multi-function button. The ringer for incoming calls is but a chirp, barely noticeable. While your phone ringer may be enough for some, I like a strong ringer on the speakerphone as well.

The K100, like other Bluetooth devices, really needs a independent power button. The K100 isn't designed for speed. To power the K100 you have to press and hold the multi-function button for about three seconds. Then to power off the K100, you have to press and hold the button for about five seconds (two tones will sound as you hold the button down).

On the bright side, you don't have to power down and up the K100 to reconnect your Windows Phone. If you leave the K100's range, simply tap the multi-function button once to reconnect things. 

Battery life is respectable. It takes about 2.5 hours to fully charge the K100 and Plantronics rates the battery life at 17 hours of talk time and 15 days of standby time. In using the K100 over the past two weeks, I found battery life to be a little better than what Plantronics rates it.

Overall Impression

The K100 is a nice Bluetooth Speakerphone. Volume and microphone performance is exceptional but the weak ringer and the lack of an independent power button really takes away from a nice speakerphone.

If Plantronics could update the K100 to have a more aggressive ringer, you could learn to live with the current button layout. As is, while the noise cancellation works great with the microphones, the background noise often muffles the ringer.

If you can rely on your phone's ringer and don't mind waiting a few seconds to power on/off the K100 and are looking for a basic speakerphone, the Plantronics it will do nicely.  However, I would be inclined to recommend the Jabra Cruiser II before I would the K100.

You can find the Plantronics K100 over at the WPCentral Accessory Store for $77.95.