4 General principles

09.143GPPApplication of ISDN User Part (ISUP) Version 3 for the Integrated Services Digital Network (ISDN) - Public Land Mobile Network (PLMN) signalling interfacePart 1: Protocol specificationTS

The gateway exchanges in both networks behave like international incoming or outgoing gateways in the relevant cases as described in EN 300 356‑1 to EN 300 356‑20 ([1] to [19]), with the exceptions indicated within this EN.