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• ITU-T Rec. Q.551 (1988)
• 1 Introduction
  • 1.1 General
  • 1.2 Definitions
• 2 Characteristics of interfaces
  • 2.1 Two-wire analogue interfaces
  • 2.2 Four-wire analogue interfaces
  • 2.3 Digital interfaces
• 3 Voice frequency parameters of a connection between two interfaces of the same exchange
  • 3.1 General
  • 3.2 Transmission loss through the exchange
  • 3.3 Group delay
  • 3.4 Noise and total distortion
  • 3.5 Crosstalk
  • 3.6 Discrimination against out-of-band signals applied to the input interface
  • 3.7 Spurious out-of-band signals received at the output interface
  • 3.8 Echo and stability
• 4 Exchange transfer function - jitter and wander