Abstract.The issue at stake is how to conceive user interfaces of IT artefacts in an organisational and semiotic perspective. Different communicative functions of user interfaces are investigated and the sequencing of user-system interaction. Two earlier models in the information systems actability approach are investigated and integrated: The Elementary InterAction Loop (EIAL) and the communicative model of user interfaces. Three new EIAL models are created dependent on three interaction modes (reading, formulation and navigation mode). A small example from eldercare is used for illustration. The foundations of the different interaction models in socio-instrumental pragmatism are discussed.