Summary: These phones will only work if your phone system supports firmware 9.3(1)SR1 or above. This is not stated anywhere on the page. Our system being a UC520 only supports up to 9.2(1) and so these phones are useless.
Summary: We are familiar with this phone since we have these in our environment already however the only thing i can say about the ones from this seller is that none of the phones had the MAC Address sticker on the back of the phone like my other ones and did not have a sticker to put it there either.
Summary: We have 500+ of these at work and have never had a problem. UNlike our old phones we can just plug and play these and the phone number follows you making desk moves a no cost this as far as phone lines go.