"The date of this letter, just two years after the patent was obtained, demonstrates the exceptional progress and evolution of this fledgling invention." (Bobby Livingston)
It was on the shores of the Grand River at Tutelo Heights, Ontario, named after a Native tribe who migrated there after the Revolutionary War, that Alexander Graham Bell first conceived the idea for the telephone in 1874. It was in a Boston laboratory that Bell, speaking to his assistant Thomas Watson, first transmitted speech through a telephone in March of 1876. That July, back in Tutelo Heights, near Brantford, Bell first successfully transmitted speech over a telegraph line. Four months later, the inventor, now a professor of speech at Boston University, received the telephone patent (http://www.brantford.ca/residents/WorkingLearning/Learning/BrantfordHistory/Pages/AlexanderGrahamBellBrantford.aspx).
Two years later, in 1878, Alexander Graham Bell wrote a letter to his parents in their Tutelo Heights home to demonstrate the ins and outs of telephone wiring. He explained: "I was quite troubled by the accident at Tutelo Heights," referring to a recent lightning strike on his parents' 10.5 acre property. "The accident shows that the earth terminals of your telephone line are defective for the current found a shorter path to the ground through two of your poles than by the proper path." (www.dailymail.co.uk/sciencetech/article-2083066/Alexander-Graham-Bell-drawing-telephone-auction.html)
Bobby Livingston, a representative for the auction company which sold Bell's letter in 2012, stated: "The early mechanics of the device [telephone] were complicated and required extreme attention to detail, without which results could be disastrous -- even fatal." Bell wanted to make sure that his parents did not have such results. He even included a detailed diagram of two telephones in his letter.
Even so, Livingston points out the success of Bell's contraption: "The date of this letter, just two years after the patent was obtained, demonstrates the exceptional progress and evolution of this fledgling invention."
Bell Homestead at Tutelo Heights, now part of Brantford, circa 1870's, courtesy http://www.museumsontario.ca/museum/Bell-Homestead-National-Histor.