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CSCve15706 - 8821 built in microphone fails after customer use



Anybody out there in CISCO world have any suggestions or helpful hints on resolving

the microphone not working on 8821 wireless phones?

thanks; Pops


33 Replies 33

YES...still going on for us as well. They haven't release any new firmware since JUL 2019!!! We are also seeing issues like-phone will only connect to one AP, phone won't power on, MIC issues. I hope CISCO will release new firmware to fix these issues soon.

We too have the issue with the phones getting stuck to one AP, we're running sip8821.11-0-5-17 and sip8821.11-0-5SR1-4, and have had this happen with both FW loads.

we never moved to firmware you mentioned because it didn't really solve any issues we are having like-MIC, one AP etc. We are on sip8821.11-0-4-14. Cisco TAC won't even attempt any troubleshooting whenever I put in a call!!! Isn't that a sign  of they know something but we don't!!!!

While I don't have even close to the number of 8821 phones most of you have, I have had so far has had the mic fail.  I don't have any coverage on mine, are they repairing them anyway?  

There is a 1yr manufacturers warranty, I think there's typically about 2 or 3 month leeway added in, I would try to RMA anything you can.  Since ours aren't covered under smartnet either, I have to call or use the chat from the Cisco website to try and RMA.  If you didn't already know, the manufacture date is down in the corner near the battery contacts.

I believe CISCO should replace all these phones for everyone regardless of 1 yr warranty. It is manufacturing defect which never existed in 7925 model.

I saw new firmware available for download.....

Cisco Employee
Cisco Employee
Cisco has found a large majority of microphone failures to be a result of using the phone with third party phone covers / cases and provides helpful suggestions in the bug workaround section which I have provided below:
Certain phone covers or cases have been found to cause or contribute to microphone failures with the Cisco 8821. Please discontinue using phone covers or cases to prevent damage to the microphone.

Ask the user to disable the background noise filter. This has been shown to work for microphones that are partially damaged

Further Problem Description:
Cisco Wireless IP Phone 8821 Support for Third-Party Cases and Covers:

Sorry, but this is no solution in my case.

We are using only original Cases from Cisco and still we have about 70-80 defective mics on 8821s. At the moment we are using about 550 of those 8821s. Those are rugged phones, there´s an EX version and a "third party supplier phone case" should cause the phone to fail?


In general we have replaced around 200 of the phones, makes around 750 phones with 200 defects... one out of four phones is not working anymore.


A real solution would be to sell replacement microphones. If you have some, let me know, we´re willing to pay for spare parts.

We had phones destroyed by colleagues (i.e. broken displays) which are NOT counting to the 200 defects, we removed the mics and fixed other 8821 which aren´t within warranty anymore... so this would be a thing to make us really happy.


It's MAY 2019---I am still seeing Microphone issues on 8821 phones. Tried everything...factory reset, new firmware etc. I hope Cisco is looking into this. These phones supposed to be better than 7925s!!!

Exactly the same problem... We have roughtly 120 Cisco 8821 now in production (and still 600 Cisco 7925)... We intended to slowly switch all our park to 8821 models...

But today after 2 years deploying progressively 8821, I have more than 30% coming back with such mic problems...

As many here, I've done everything to try to resolve this issue (reset to factory, firmware updates, etc...) but it really seems to be a hardware problem.

It's just unbelieveble that Cisco don't do anything for that !! Our account manager even don't seems to be aware of that problem !

The problem is that we're blocked, 7925 are not orderable no more and 8821 are really not reliable... What can we do ?! Is there a Cisco roadmap for a new wireless phone model ?!

We´re not buying Cisco anymore.


Cisco isn´t even customer-orientated as much to act as they should. There is a failure on that product, it was never working well, it´s dying like a fly and they should refund money and stop that phone.


Alternatives are i.e. the Ascom I62.

There are even Cisco gold partners who aren´t selling this thing anymore.


And the best alternative is DECT over IP. Just google for it... we had ~40 antennas in our plant and could also reach the parking lot and signal was available on the roof of the buildings. Today ~230 antennas, no signal on parking lot, building roofs, even the fences are not reachable and we have still some areas with weak signals... 
Just. go. DECT.

I hear you....I have been sending all the bad phones back to Cisco for last few months. No one knows what is going on with mic situation!!! One time I heard that Cisco has been looking for different manufacturer for mic...not sure how true that is?


Are these ASCOM phones would work with same  infrastructure as Cisco phones? What is the average cost of each phone?

We're replacing a very reliable (but EOL) Spectralink 900 MHz system with 8821's and I'm enemy #1 here at work now.  The handsets were fairly basic - and we replaced a fair number of them due to wear, tear and abuse - but the system simply worked well in an industrial environment.   Even the guy who helped put it in (who's now selling industrial headsets, mics, etc... for radios) said we'd regret it.  He's right!  Good times.  But need to move forward as we can't rely on grey-market / refurb equipment forever either.  

Today, I installed the latest firmware sip8821.11-0-5SR2-2 on a phone which was only seeing one access point. It didn't do anything!!! Problem remains the same-----
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