ABSTRACTS OF TECHNICAL ARTICLES 859 



requirements the network must not cross-talk into associated circuits 

 and must have desirable impedance characteristics in the attenuation 

 range of frequencies as well as throughout the transmission range. 

 An illustration of the use of transmission networks in a typical three- 

 channel carrier telephone system is given describing the functions of 

 the line filter sets, the directional filter sets, band filters, and equalizers. 

 Some of the engineering limitations on the design and construction 

 of networks are discussed. 



Recent Developments in Telephone Construction Practices}^ B. S. 

 Wagner and A. C. Burroway. In this paper are described some 

 recent developments in telephone cable installation and maintenance 

 practices. The paper is divided into three sections: (1) Gas pressure 

 testing for detecting and locating sheath defects before they result in 

 failure. (2) Methods for reducing bowing and other movements of 

 cable which in time cause fracture of the sheath. (3) Catenary con- 

 struction for long spans, such as at river crossings. 



iM. /. E. E. Journal, Vol. 48, May, 1929, pp. 366-369 (abridgment). 



