"When you telephone, the other person cannot see you. He judges you by your voice. As with any sort of communication device, be it a letter or through the floo, etiquette and deportment are important. Now, people use the telephone to make business calls, they use it to talk with friends, placing orders with the apothecaries, grocers, and the butcher. The telephone can be used to contact the Aurors or Healers in case of an emergency. When using a telephone, there’s no need to shout unless you are in a busy location where there is a lot of background noise. In a calm setting such as in your own home, or in the booths that have been set up in your common rooms; all you need to remember is to speak as if the other person is in the room with you."