There are loads of problems with these. I would seriously recommend - no insist that you load the latest SR6 release as you have done. Failure to do so could "brick" your phones and then you need to RMA them. There are also loads of recommendations for the wireless environment - there is a 200+ page document you need to go through as well.
8821 phones are particulary picky phones regarding the wireless enviroment that is required for them to work properly.
8821 have a deployment guide that you must follow if you want the phone to perform at its best, please read it carefuly and throughtly.
Best Regards, Jaime.
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Recently deployed 464 wireless 8821 SIP phones and the most recent troubles are:
1. Magnet strip for charging becomes dislodged and left in multi-charger.
2. The middle battery "copper" connection inside device comes lose or falls off.
3. The device will mysteriously turn back on when power button is pressed and device powers down?
We did have the other issues listed and upgraded firmware provided from Cisco engineers (not published firmware on Cisco.com). For the most part the devices have replaced the 7925 SCCP devices, but we have had some learning curves during deployment. I recommend following the read me when installing and provide a stable 5 GHz wireless network. The wireless controllers and SIP profile on CUCM is crucial and some profile timers will make or break you. The USB connection when programming devices will give you fits, and I have abandoned trying to program devices this way if the device will not conform. Finger banging the profile, SSID and pre shared key is mentally easier than trying to break into the phone with USB connection (on some not all).
Leo, we were informed from Cisco that this anomaly was repaired on devices manufactured after 01-01-18. Cisco is unable to confirm what S/N or lot numbers can confirm manufacture date after repair statements (bug) was made. Our test program included 34 8821 devices deployed 03-10-18 that rendered 7 devices with this defect. Full deployment of 464 on 07-09-18 has not returned this defect (yet), however the middle battery connection has development with 6 devices to date. Overall the 8821 is a bit tempestuous and Cisco is riding the storm to provide a stable platform.
i experience weird issues also
have 5 of those at a deployment.
2 of them at totally random intervals appear turn them selves off while on charger.
i think they just crash.
i turn them back on and they are fully charged.
is not everyday totally random.
the other 3 have no issue or so ever
installed the latest firmware and seems made some difference but insident occured again after a couple weeks.