Requirements elicitation and analysis
This might involve: business analysts, systems analysts, sales managers, pre-sales support, sales engineers depending on the environment and the particular circumstances of the project (e.g. is it being developed for an internal or external client?).
The ISO 12207 suggests that ‘human factors engineering specifications’ would be produced at this stage which implies the deployment of human-computer interface specialists
Other specialists might be involved to deal with other technical areas, for example security.