PlantronicsVista M22 Audio Processor

Good product.

I work from home. The company I work for has me take customer calls via a VoIP phone. The volume during calls would randomly become so quiet I could not hear the person speaking or so loud that my ears literally would hurt. There would be random loud crackling sounds, high pitched noises, etc during the call, too. My manager had no idea what could be causing it. After several months, I noticed that I was having a harder time hearing those around me, TV, etc. I became worried that my job was making me deaf.I did some research, found that this was compatible with my headset, and bought it hoping it regulate the sounds coming from my headset.IT WORKED WONDERFULLY!!I no longer have to deal with the headset volume randomly becoming exceedingly loud or quiet. The volume remains the same throughout the call and for every call. As an additional benefit, this device also boosts my voice so I no longer have to yell for my callers to be able to hear me. Well, for the most part. There are some callers that are hard of hearing or in a extremely noisy area that I still need to speak louder for them to hear me, but most callers can now hear me fine.I highly recommend this product!!

It's actually not bad as other reviewers said. For transmitting volume (mic volume), I actually did a test by calling my home phone number from my dedicated work number (with M22 hooked with a binaural headset) and left a voice message. I then listened to the voice message I left - it sounds loud and clear with no "mumbling". Although this seems to be the result of combining M22 and a headset with good microphone. But for M22, you can turn the little white dial on the side to increase or decrease microphone volume. As for hearing volume, I think it depends on the caller's phone quality. M22's Amplification ranges from 1 - 9 according to your preference. At 5, the dial tone is pretty loud. I tested the hearing volume by calling my phone provider (A*&T) and listened to their automated menu/options. Clear with no mumbling. But when I was on the phone with customers, I had to turn the hearing volume to 8 - 9. The calls I received might have been transferred a couple times before getting to me therefore this might be the problem why some calls were so quiet. Also, my phone has its own hearing volume control and I found that if I turn both the M22 hearing voume and the one on my phone to maximum, I would start hearing "wee wee wee" noise in the background. Therefore I had set the built-in volume control of my phone to medium low. Everything went great then.

Works great with our Fujitsu phones and the sound is crystal clear.

Plusses...The mute and volume(listening) buttons are right on top. Easy to plug in and use...Really Big Downside is that the speaking volume control is under a panel you have to remove AND adjust the volume with a tool! If you are on a call and want to turn your volume up, you have to almost dismantle the amplifier! Really inconvenient and not at all practical.. Why couldn't they put the volume control on the top or side?Had I known it was such a hassle just to change the speaking volume, I would have probably not bought it

I now know why there is no power adapter offered with this unit. It works fine on battery. However, I've tried 2 different power adapters and the same issue happens with either. When using a power adapter, the unit creates 'static' on the line making it totally useless. So, I returned the unit.

This item arrived before the estimated 2 weeks... wonderful job! Per Plantronics' description of this M22 on their website, this amplifier works extremely well with select analog phones (never tried the VOIP ones). I am using this with an AT&T CL4940 (until I get my much preferred Panasonic phone delivered this week), combined with the HW261N headset for my telecommuting job. The combo produces a loud and clear voice transmission--both incoming and outgoing--while in 8-hour phone and web conferences. Even the noise-cancelling feature of the microphone works well enough to completely drown out the lawn mower and the occasional barking of the neighbor's dogs! Not a bad product at all. Slight quibble, however, and my reason for a 4 star... this item was advertised by seller as 'new'. However, it arrived with no cover for the side switches. Other than that, I'm happy with the M22 so far! I will definitely buy another one of these in the near future to serve as a backup.Update 7/1/13: The M22 developed a bad humming sound that can be heard from the caller's side. Even when I tried changing the power adapter to batteries only, the same issue persists. The replacement I asked for had the same problem. It is too late to return this and the other amplifier since it has been more than 30 days. By the way, this amplifier was never dropped or anything. It sits on my desk and is used for work only. This frequent humming issue does not justify the high cost of this purchase. 4 stars down to 1 star (0 if possible).

We have a small call center and we use these with our Shoretel phone system. They are reasonably priced but do a good job. They seem to hold up for about two years of steady use.