Umbilical device, where the device has a longitudinal axis, and includes at least one elongated electrical cable or tube element; and an elongated load bearing component along the longitudinal axis and having an external surface including at least one groove disposed along the longitudinal axis and parallel thereof. The seat assembly is mounted on a base of a chair. The tube sheets and tubes are formed of the same material, which facilitates their joining by means of joints that are substantially galvanic corrosion-resistant joints. A test signal component contained in the output signal is monitored. The user’s email accounts may be accessed on behalf of the user based on the email addresses and account access data in the user’s folder. The MRL layer is technology independent and uses the information received from the underlying technologies to select the most appropriate uplink and downlink technologies to match the respective service requirements.