The downlink process is the way a sensor can receive data from the network. This process is really useful if you need the device to execute an action or if you want to change the sensor behavior.
This post is as some other of my LpWan series a video post in French completed by this text post in english.
When you plan to deploy / sell sigfox based solution to consumer, you have to manage you device park. The sigfox network have a restricted radio medium to ensure you will not emit more than what you payed for you will be charged by them if a device you own is emitting, even if it is emitting out of your control. There is no network subscription like in 3G before being able to emit so anyone can emit. That is why, to ensure every one is clear, you have an extra cost if you emit more than you are allowed or if you emit from a non registered device.
When you are designing end-user system you have no control on the device and if you propose a monthly fee to use your solution you will never sure the end user will unplug it once he stop to pay for your service. It means you could have a consumer stopping to pay for your service but a device continuing to emit and sigfox request you to pay for it.
Since the network allow you to have downlink message, now you have the capability to send order to your device and as a consequence allowing you to kill the device remotely. This is a good solution !
Next you have a new scenario where your end user finally decide to reuse your service and want to reactivate the device. At this step you won’t be able to communicate with it and you will have to find another way to reset its state to normal. You can eventually add a “factory reset” button or request to reflash it. There is another funny when : playing with the reboot time.
This post will describe how to lock a device to stop emit on network and how to play with the startup sequence to reset it. Read more !