On 1 February 1878, Duquet was granted a Canadian patent for a telephone receiver, that was used in some early types of handsets. This patent was for a new transmitter based on a cluster of permanent magnets that improved signal clarity, and a new mouthpiece design. Later, Duquet worked on combining transmitter and receiver in one unit, arranged both on each end of a board. The first telephone installed in Montreal was one Duquet designed, and he installed other phones and phone lines in the area.
