The present document defines the stage one of the Explicit Call Transfer (ECT) supplementary service for the
pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications
operators. Stage one is an overall service description from the users point of view (see CCITT
Recommendation I.130 [1]), but does not deal with the details of the human interface itself.
The present document defines the interworking requirements of private ISDNs with the public ISDN.
In addition the present document specifies the base functionality where the service is provided to the user via a private
ISDN.
The present document does not specify the additional requirements where the service is provided to the user via a
telecommunications network that is not an ISDN but does include interworking requirements of other networks with the
public ISDN.
Interactions with supplementary services not listed in clause 8 are outside the scope of the present document.
Charging principles are outside the scope of the present document.
The ECT supplementary service enables a user who has two calls, each of which can be an incoming call or an outgoing
call, to connect together the other users in the two calls, into one call.
The ECT supplementary service is applicable to all circuit-switched basic telecommunication services.
The present document is applicable to the stage two and stage three standards for the ISDN ECT supplementary service.
The terms "stage two" and "stage three" are also defined in CCITT Recommendation I.130 [1]. Where the text indicates
the status of a requirement, (i.e. as strict command or prohibition, as authorization leaving freedom, as a capability or
possibility), this shall be reflected in the text of the relevant stage two and stage three standards.
Furthermore, conformance to the present document is met by conforming to the stage three standards with the field of
applicat (...abbreviated)