METALLIC MATERIALS IN THE TELEPHONE SYSTEM 151 



The trends in the use of new metalHc materials in the telephone service 

 are difficult to predict. A large class of applications includes the in- 

 corporation of improved materials in existing apparatus with some 

 modification in design resulting in a cost saving or in improved service. 

 Such materials originate from developments by the metallurgical in- 

 dustry and from investigations by the System's engineers. Examples 

 of this type have already been mentioned; for example, improved cable 

 sheathing materials, electrical conductors, and magnetic alloys. This 

 evolution in application of materials will undoubtedly continue and 

 constitute a large part of the telephone metallurgists' activities. 



There is another field of application for metallic materials, applica- 

 tions in newly designed apparatus or systems of communication. Here 

 the properties of existing materials are frequently inadequate to per- 

 form the required duties and new materials must be developed with the 

 necessary properties. One example already cited is the preparation of 

 magnetic powder for inductance coil cores. A new system of trans- 

 mission, a million-cycle system, requires newly developed materials in 

 the coaxial cable and the associated equipment. Special properties 

 are usually involved which are of interest only in connection with 

 communications, and hence the development of such materials is 

 dependent almost wholly on the activities of the System's research 

 groups. 



