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• ITU-T Rec. Q.554 (1988)
• 1 General
• 2 Characteristics of interfaces
  • 2.1 Interface characteristics common to digital interfaces
  • 2.2 Interface characteristics at interface A
  • 2.3 Interface characteristics at interface B
  • 2.4 Interface characteristics at interface V1
  • 2.5 Interface characteristics at other V-type interfaces
• 3 Characteristics of 64 kbit/s half connections
  • 3.1 Half connection characteristics common to all digital interfaces