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
Disclosure of the invention under the European Patent Convention patent application as filed, consisting in an insufficient identification of the subject-matter claimed, cannot subsequently be cured without offending against Article 123(2) EPC which provides that the subject-matter content of a European patent application as filed may not be extended. An insufficiently clear and complete disclosure of the invention is a ground of opposition, and revocation. Although the European Patent Convention does not exclude the patenting of "revolutionary" inventions,<ref name="T 1329/07"> Decision T 1329/07 of the Technical Board of Appeal 3.4.02 of 11 November 2010, point 2.2.3</ref> The burden of proof generally lies upon an opponent to establish insufficiency of