We want to develop a box to link a device with us (connected in serial) and our cloud.

Definitions Link +: The box to develop SCE: System Cash Register FDM: Fiscal Data Module User: Person to whom Link + is intended Objectives The law requires our users to have an FDM that must be physically installed at home. We want to develop Link + allowing users to have an SCE approved by the SPF finance operating via the cloud at low cost. To do this users will connect the FDM Link + and it will tunnel to our cloud to access the FDM user. Characteristics - Bluetooth - Wireless - Port db9 male (serial) - Red LED - Green LED - microUSB power supply - Linux - Sufficient CPU power to operate nodejs Explanation The goal is that Link + silk is the easiest way for users to use. They plug it into the socket, they connect the FDM on Link + and that's it. The configuration will be done via the user's smartphone in the same way as Google's Chromecast. The user will launch an application on their smartphone, this one will make a Bluetooth search and will be paired with Link +. The app will send the Wifi settings to Link + so that it can connect to the Wifi. Link + will initiate a tunnel to our cloud, the cloud will then use this tunnel to communicate with the FDM when necessary. Cost Link + must be the cheapest possible to develop and produce, it only supports users to use the cloud. Our customers are few, we want to produce series of 100 Link +