For communicating between an Internet of Things (IoT) device and a remote computer system, the IoT device transmits an upload data message via a close range communication circuit to a mobile communication device, for forwarding to the remote computer system. The remote computer system receives the upload data message via a mobile radio communication network and stores an address of the mobile communication device, as a communication relay address for the IoT device. The remote computer system transmits a download data message via the mobile radio communication network to the communication relay address, for forwarding to the IoT device. The IoT device receives the download data message from the remote computer system, as forwarded by the mobile communication device via the close range communication circuit.