REFERENCE SYSTEM FOR TELEPHONE TRANSMISSION 559 



Laboratories in New York and the other in the laboratory of the 

 C.C.I, in Paris. The C.C.I, further recommended that primary and 

 working standard systems, used in the telephone administrations 

 adhering to the C.C.I., be calibrated in terms of the Master Reference 

 System. The establishment of these two master systems insures the 

 use of a common base line for the expression of transmission standards, 

 and for the ratings of the transmission performance, of telephone 

 circuits in the two continents where the telephone system has had its 

 greatest development. 



