Network interfaces

Embedded devices often integrate one or more communication interfaces. Many microcontrollers integrate the Media Access Control (MAC) portion of an Ethernet interface, so connecting a Physical Layer Transceiver (PHY) would enable LAN access. Some devices are coupled with radio transceivers, operating at fixed frequency ranges and implementing one or more protocols to communicate over wireless links. Frequently used frequencies for wireless communication are the 2.4 GHz band, in use by Bluetooth and 802.11 Wi-Fi, and some specific ISM ranges of frequency below 1 GHz, which depend on local regulations. Usable sub-GHz frequencies include the 868 MHz ISM band in the European Union and the 915 MHz ISM band in the US. Transceivers are usually designed to access the physical layer according to specific link protocols, regulating shared access to the physical media among two or more devices. While two interfaces accessing the same media can have different configurations...