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Private Integrated Services Network (PISN) - Inter-exchange signalling protocol - Advice of charge supplementary services (QSIG-AOC)

3rd edition, December 2001

This Standard specifies the signalling protocol for the support of the Advice Of Charge supplementary services (SS-AOC) at the Q reference point between Private Integrated services Network eXchanges (PINX) connected together within a Private Integrated Services Network (PISN).

SS-AOC is a set of supplementary services which enable a user to receive information about the charging of its calls that leave the PISN and enter another network.

The three AOC supplementary services are:

  1. Charging information at call set-up time (AOC-S) SS-AOC-S enables the user to receive information about the charging rates at call set-up time and also to receive further information during the call if there is a change of charging rates.
  2. Charging information during the call (AOC-D) SS-AOC-D enables a user to receive information on the recorded charges for a call during the active phase of the call.
  3. Charging information at the end of the call (AOC-E) SS-AOC-E enables a user to receive information on the recorded charges for a call when the call is terminated.

The Q reference point is defined in ECMA-133.

Service specifications are produced in three stages and according to the method specified in ETS 300 387. This Standard contains the stage 3 specification for the Q reference point and satisfies the requirements identified by the stage 1 and stage 2 specifications in ECMA-211.

The signalling protocol for SS-AOC operates on top of the signalling protocol for basic circuit switched call control, as specified in ECMA-143, and uses certain aspects of the generic procedures for the control of supplementary services specified in ECMA-165.

This Standard also specifies additional signalling protocol requirements for the support of interactions at the Q reference point between SS-AOC and other supplementary services and ANFs.

NOTE – Additional interactions that have no impact on the signalling protocol at the Q reference point can be found in the relevant stage 1 specifications.

This Standard is applicable to PINXs which can interconnect to form a PISN.

The protocol defined in this Standard forms part of the PSS1 protocol (informally known as QSIG).

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CategoryData communication – PISN


Technical CommitteeTC32

ISO/IEC number15050

ETSI numberEN 301 264


  • ECMA-212, 1st edition, December 1994Download
  • ECMA-212, 2nd edition, June 1997Download