A method of communicating between an Internet of Things device and a remote computer system , the method comprising: receiving in the Internet of Things device a secured data package from a mobile communication device via a close range communication circuit; decrypting in the Internet of Things device the secured data package, using a cryptographic key stored securely in the Internet of Things device ; extracting in the Internet of Things device from the secured data package an identifier of a back-end system associated with the remote computer system , and storing the identifier of the back-end system in the Internet of Things device ; transmitting via a the close range communication circuit an upload data message for the remote computer system from the Internet of Things device to the mobile communication device , within the close range of the Internet of Things device , for forwarding to the remote computer system via a mobile radio communication network, the upload data message including a unique identifier of the Internet of Things device and the identifier of the back-end system stored in the Internet of Things device ; receiving in the remote computer system the upload data message from the Internet of Things device , as forwarded by the mobile communication device via the mobile radio communication network; storing in the remote computer system an address of the mobile communication device , as a communication relay address , linked to the unique identifier of the Internet of Things device ; transmitting via the mobile radio communication network a download data message for the Internet of Things device from the remote computer system to the communication relay address linked to the unique identifier of the Internet of Things device , for forwarding to the Internet of Things device ; and receiving in the Internet of Things device the download data message from the remote computer system , as forwarded by the mobile communication device via the close range communication circuit. receiving in the Internet of Things device a secured data package from a mobile communication device via a close range communication circuit; decrypting in the Internet of Things device the secured data package, using a cryptographic key stored securely in the Internet of Things device ; extracting in the Internet of Things device from the secured data package an identifier of a back-end system associated with the remote computer system , and storing the identifier of the back-end system in the Internet of Things device ; transmitting via a the close range communication circuit an upload data message for the remote computer system from the Internet of Things device to the mobile communication device , within the close range of the Internet of Things device , for forwarding to the remote computer system via a mobile radio communication network, the upload data message including a unique identifier of the Internet of Things device and the identifier of the back-end system stored in the Internet of Things device ; receiving in the remote computer system the upload data message from the Internet of Things device , as forwarded by the mobile communication device via the mobile radio communication network; storing in the remote computer system an address of the mobile communication device , as a communication relay address , linked to the unique identifier of the Internet of Things device ; transmitting via the mobile radio communication network a download data message for the Internet of Things device from the remote computer system to the communication relay address linked to the unique identifier of the Internet of Things device , for forwarding to the Internet of Things device ; and receiving in the Internet of Things device the download data message from the remote computer system , as forwarded by the mobile communication device via the close range communication circuit. <EOS>