A small unit that serves as a temporary store of data; typically patient related data given from other devices, e.g., patient monitors or analysers which are not connected to a network, or are in a transport phase. This data is stored in this module's memory for transfer to a permanent store, e.g., the patient's electronic journal. It is designed to operate as part of a patient monitoring system enhancing the function of this system (the parent device). The module automatically plugs into the parent device when the user places it into a standardized slot in the parent device.