ETSI TS 122 091 specifies the stage 1 description of Explicit Call Transfer (ECT) from the service subscriber's and user's points of view, in particular:

• the procedures for normal operation with successful outcome;
• the action to be taken in exceptional circumstances;
• the interaction with other supplementary services.

The present document does not deal with the Man-Machine Interface (MMI) requirements, but makes reference to the appropriate Technical Specifications.

The charging principles applied to ECT are established in the present document in terms of the charging information required to be collected. Any subsequent charging implications are outside of the scope of the present document.

Any interactions with other networks not dealt with in Clause 9 are outside the scope of the present document.