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 access network
 ISDN connection
 example: 30B+D
 (2.048 Mb/s)
  
 Twisted pair - connection
 Private Branch Exchange
 Multiplexer
 
 On-line subscriber
 with several telephones
  
 
 
 Wireless
 access
 (or radio access
 point)
  
 Distribution point
 Cross connection point
 
  
  
  
  
  
  
 
  
  
  
  
 
 
  
   
   
   
  
  
  
   
   
  
 
  
  
  
  
 
  
  
  
 
  
  
  
  
 
 Q.512 specifies
 exchange interfaces