Dialogic logo

ISDN: theory and practice

  Introduction  
 
  Basic Concepts  
     10 pages
  B & D channels  
     16 pages
  ISDN Networks  
     9 pages
  Bearer Capabilities  
     8 pages
  Voice, Fax, and Modems  
     15 pages
  Terminology  
     10 pages
  Device Addressing  
     8 pages
  Call Setup  
     16 pages
  Managing inbound calls  
     11 pages
  Rate Adaptation  
     9 pages
  Cabling  
     13 pages
  Further information  
 
  << Back     Next page >>  
What is ISDN?
  • It is important to remember that ISDN channels cannot be be divided up into smaller units. Each is provided on an "all or nothing" basis.
  • Two users communicating over a B channel have 64 000 bits per second available to them. There is nothing they can do to reduce this bandwidth.
  • What about the situation where the two users find that 64 000 bits per second is not sufficient? The only solution is to add another B channel. This gives them 128 000 bits per second. They are not using a single B channel of 128 000 bits per second. (Don't forget that the speed of a B channel is defined as 64 000 bits per second. Anything which operates at a different speed isn't a B channel.)
  • This means that they will have two parallel calls between them and the phone bill will show two simultaneous calls.

Copyright© 2016 Dialogic® Corporation. All rights reserved. Legal Notice
S2P1.htm 10 1360