Invention of the telephone useful and widespread apparatus it is now. The telephone exchange was an idea of the Hungarian engineer Tivadar Puskás (1844–1893) in 1876, while he was working for Thomas Edison on a telegraph exchange. Puskás was working on his idea for an electrical telegraph exchange when Alexander Graham Bell received the first patent for the telephone. This caused Puskás to take a fresh look at his own work and he refocused on perfecting a design for a telephone exchange. He then got in touch with the U.S. inventor Thomas Edison who liked the design. According to Edison, "Tivadar Puskas was the
Condenser telephone (copper or steel) circuit for both legs of the circuit. This basic telephone circuit was known as a Buzzer, or more commonly, a Condenser Telephone Circuit. A patent registered by François van Rysselberghe (1846-1893) in 1882 is thought to be the original invention of the basis of the phonopore (condensor) method. The technique was developed and improved by Charles Langdon-Davies in 1890, particularly with the invention of a method to call between phones Patents were lodged for improved versions of instruments for commercial use including one lodged by Ellis F Frost in 1902. The system worked over a single aerial