Invention of the telephone hardly a commercially practical telephone in the modern sense. Thomas Edison tested the Reis equipment and found that "single words, uttered as in reading, speaking and the like, were perceptible indistinctly, notwithstanding here also the inflections of the voice, the modulations of interrogation, wonder, command, etc., attained distinct expression." In 1947, the Reis device was tested by the British company Standard Telephones and Cables (STC). The results also confirmed it could transmit and receive speech with good quality (fidelity), but relatively low intensity. At the time STC was bidding for a contract with Alexander Graham Bell's American Telephone and Telegraph
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