Context: Returning home to Brantford after six months abroad, Bell continued his experiments with his "harmonic telegraph".[N 12] The basic concept behind his device was that messages could be sent through a single wire if each message was transmitted at a different pitch, but work on both the transmitter and receiver was needed.

Question: How many wires did Bell send a signal through?
Answer: 1

Question: For  his system to work, Bell had to change what about each code?
Answer: pitch

Question: Bell needed to fix both the transmitter and what?
Answer: receiver

Question: Where was Bell's home?
Answer: Brantford