This paper reports on longitudinal research into the implementation and use of the first mobile Vehicle Mounted Data System (VMDS) at a UK fire service. Using insights from Claudio Ciborra’s work, the paper develops a phenomenological ontology for conceptualising the organisational relation with information technology. The paper sets out how the brigade’s mobile data system can be understood in terms of hospitality, improvisation and Gestell. The paper argues that despite the seemingly innocent and potentially mundane replacement of paper-based practices by electronically mediated information and communication, the VMDS is associated with significant and far-reaching outcomes, both empirical and ontological, within the brigade and for the modernisation of fire service provision across the UK. The paper concludes with implications for a phenomenology of information technology.