It would be great if Telepathy/KDE would provide a page in the settings to configure and test the microphone and the webcam. My webcam, for example, often just provides a very dark picture, and I have to manually select the correct microphone. Thus I would like to have a testing page to see whether everything works as intended, before I make a call.
Dear user, unfortunately Telepathy is no longer maintained. Please migrate to another solution, e.g. for Jabber a possibility is Kaidan, for Matrix a candidate is NeoChat.