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    | Switching: 
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    | Transfer
    modes & connections 
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    | - developed for
    voice 
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    | - nowadays also
    for data 
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    | - well-specified
    delays 
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    | - echo problems 
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    | - developed for
    data 
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    | - nowadays also
    for voice 
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    | - Statistical
    multiplexing 
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    | - variable delays 
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    | - broadcasting 
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    | - modest error
    rates 
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    | often accepted 
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    | - fast data in
    good channels 
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