The present document provides the service requirements for operation of the MCData service. MCData makes use of capabilities included in Group Communication System Enablers@ Proximity Services@ Isolated E-UTRAN operation for Public Safety and Mission Critical Services Common Requirements with additional requirements specific to the MCData Service. The MCData Service can be used for public safety applications and also for general commercial applications (e.g.@ utility companies and railways). The requirements in this specifications do not apply to GSM or UMTS.