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TechSpec
  • Foreword
  • 0 Scope
  • 1 Framework for the description of telecommunication services
  • 2 Description of circuit telecommunication services by the attribute method
  • 3 Characterization of circuit telecommunication services
  • 4 Provision of telecommunication services
  • A.1 Information transfer attributes
  • A.2 Attributes describing the access at the user equipment
  • A.3 Interworking attribute
  • A.4 General attributes
  • B.1 High layer attributes
  • B.2 Low layer attribute (bearer capabilities)
  • B.3 General attributes
  • C.1 Scope
  • C.2 Network Determined User Busy (NDUB) condition
  • C.3 User Determined User Busy (UDUB) condition
  • C.4 Mobile subscriber busy
  • D.1 Scope
  • D.2 Mobile Originated Call Set-up
  • D.3 Mobile Terminated Call Set-up
  • F.1 General
  • F.2 Supervisory tones
  • F.3 Recorded announcements
  • F.4 Application of call control cause information elements to supervisory tones

C.3 User Determined User Busy (UDUB) condition

22.0013GPPPrinciples of circuit telecommunication services supported by a Public Land Mobile Network (PLMN)Release 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

This condition occurs when a call is offered to a user equipment and the UE responds "user busy" because the subscribers resources (terminal or person using them) are busy. Then the PLMN will clear the call with the indication "busy" back towards the calling subscriber (see also clause 4).