CONTENTS

 1     Introduction      
 2     References 
 3     Echo control in telecommunication networks         
        3.1     Echo control devices          
        3.2     General echo control considerations from a PSTN perspective       
        3.3     Additional echo control considerations from the perspective of interconnected networks                   (e.g., private networks, the Internet)    
        3.4     Application-related echo control considerations      
        3.5     Voiceband data modem constraints
 4     Application rules and operational constraints         
        4.1     Public network transmission planning          
        4.2     Delay considerations          
        4.3     Provisioning of the echo path capacity and echo path characteristics
        4.4     Echo canceller transmission planning for multiple interconnected networks (e.g., public, private, Internet)    
 5     Network and service evolutionary considerations  
        5.1     Bit transparency of echo cancellers 
        5.2     Non-linearities and time variant effects in the echo path       
        5.3     Low bit-rate coding between tandem cancellers      
        5.4     Tandeming of Echo Cancellers       
        5.5     Convergence speed           
        5.6     Acoustic echo control and environments     
        5.7     New circuit-switched service         
        5.8     Comfort noise        
 6     Special CME networking considerations  
        6.1     Detailed interaction
        6.2     Possible solutions   
Appendix I – Echo path dispersion time    
        I.1        Echo-path characteristics from measurements in North America    
Appendix II – Multiple Tail Circuits    
       II.1     Multiple tails in a typical bridged telephone call (North America)