International Standard
ISO/IEC 15056:1997
Information technology — Telecommunications and information exchange between systems — Private Integrated Services Network — Inter-exchange signalling protocol — Transit counter additional network feature
Reference number
ISO/IEC 15056:1997
Edition 1
International Standard
Read sample
ISO/IEC 15056:1997
Published (Edition 1, 1997)
This standard was last reviewed and confirmed in 2015. Therefore this version remains current.

ISO/IEC 15056:1997

ISO/IEC 15056:1997
CHF 63
Convert Swiss francs (CHF) to your currency
The electronic version of this International Standard can be downloaded from the ISO/IEC Information Technology Task Force (ITTF) web site


This International Standard specifies the signaling protocol for the support of the Transit Counter additional network feature (ANF-TC) at the Q reference point between Private Integrated Services Network Exchanges (PINXs) connected together within a Private Integrated Services Network (PISN). ANF-TC is a feature that limits the number of Transit PINXs that a call setup request may be routed through e.g., to protect the network against indefinite looping. The Q reference point is defined in ISO/IEC 11579- 1. Service specifications are produced in three stages and according to the method specified in CCITT Recommendation I. 130. This International 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 ISO/IEC 15055. The signaling protocol for ANF-TC operates in association with the signaling protocols for basic circuit switched call control (as specified in ISO/IEC 11572) and call independent (connection oriented) signaling connections (as specified in ISOIIEC 11582). This International Standard also specifies additional signaling protocol requirements for the support of interactions at the Q reference point between ANF-TC and other supplementary services and ANFs. This International Standard is applicable to PINXs that can interconnect to form a PISN.

General information

  •  : Published
     : 1997-05
    : Close of review [90.60]
  •  : 1
     : 11
  • ISO/IEC JTC 1/SC 6
  • RSS updates

Got a question?

Check out our Help and Support

Check out our FAQs

Customer care
+41 22 749 08 88

Opening hours:
Monday to Friday - 09:00-12:00, 14:00-17:00 (UTC+1)