THE BELL SYSTEM 



TECHNICAL JOURNAL 



VOLUME XXXV MARCH 1956 number 2 



Copyright 1958, American Telephone and Telegraph Company 



An Experimental Remote Controlled 

 Line Concentrator 



By. A. E. JOEL, JR. 



(Manuscript received June 30, 1955) 



Concentration, which is the process of connecting a number of telephone 

 lines to a smaller number of switching paths, has always been a funda?nental 

 function in switching systems. By performing this function remotely from 

 the central office, a new balance between outside plant and switching costs 

 may be obtained which shows promise of providing service more economi- 

 cally in some situations. 



The broad concept of remote line concentrators is not new. However, its 

 solution with the new devices and techniques now available has made the 

 possibilities of decentralization of the means for switching telephone con- 

 nections very promising. 



Three models of an experimental equipment have been designed and con- 

 structed for service. The models have included equipment to enable the evalua- 

 tion of new procedures required by the introduction of remote line concentra- 

 tors into the telephone plant. The paper discusses the philosophy, devices, 

 and techniques. 



CONTENTS 



1 . Introduction 250 



2. Objectives 251 



3. New Devices Emploj^ed 252 



4. New Techniques Emploved 254 



5. Switching Plan ". 257 



249 



