GSM-R (GSM-Rail) is a digital radio system tailored for railway communication, based on GSM technology. It supports voice, data, and traffic control functions for railways, including the Electronic Train Control System (ETCS). GSM-R incorporates specialized features for rail environments, ensuring secure communication for train operations and railway personnel. It operates in the frequency band of 876 – 880 MHz / 921 – 925 MHz across Europe and has an extension band in some countries. GSM-R serves as the European standard for railway communications, promoting interoperability among railway companies. Its successor, FRMCS, is currently in development.