Hi Weston, I think the question is a little to vague to answer. What kind of setup or cordless phone are you referring to? Sound quality on the mobile app can definitely vary depending on the quality of the 3G/4G signal or the wi-fi connection. Cordless phones can also vary quite a bit depending on their frequency and outside interference.
We presently use RC via our iPhones (4 max at a time) using a very strong wi-fi connection, with a properly configured ASUS Dark Knight router. When we receive an email, or another call comes in, it disrupts the present call. We are considering purchasing the Yealink phones you sell. Prior to purchasing, I want to ensure the call quality will be much better. Your thoughts?