the first telephones consisted of a wooden box which resembled a camera. the mouthpiece was a two-inch tube that had an opening into a cavern air chamber that had in the back a 4.5 inch round plate of sheet iron. this box telephone consisted a large "u" shaped, horseshoe magnet with an iron core attached to each pole. the soft iron core attachments were wound with a spool of small gauge insulated wire. the electrical current generated by the spools of wire related to the waveform of person's voice spoken into the mouthpiece. the whole mechanical gadget was bulky and awkward and did not respond well to a person's voice.