The wireless network shares the company's name: Sigfox. It uses Ultra NarrowBand technology with a transmission frequency of 100 Hz and operates at 868 MHz on the free ISM band. Sigfox can transmit only very small messages of 12 bytes maximum, and only up to 140 times a day. This is, however, enough to handle tax codes or coordinates, for example.
Up until now, companies that wanted to use Sigfox had to purchase the wireless modules from Sigfox partners such as Texas Instruments, STMicroelectronics or NXP. Publicly releasing the specifications of the 3D Ultra NarrowBand wireless protocol is an effort to encourage other companies to offer corresponding modules for sensors or trackers. According to the specifications, Sigfox messages can be encrypted at 128-bit AES. A soon-to-be-released document is said to contain more details.