Repeater GSM, 3G and 4G signal at frequencies 800 MHz, 900 MHz, 1800 MHz, 2100 MHz and 2600MHz. 900/1800 MHz frequency is used in GSM mobile phone for digital voice transmission. 900/1800 MHz frequency is used in GSM mobile phone for transmitting data and 3G frequencies 800/2600 MHz 4G for transmitting data. Ideal for increasing the quality of mobile phone signal in Entorwhere we lack quality. The typical installation could be an interior room (poor signal quality), where the GSM repeater is placed, while outside the receiving antenna (good signal quality) is placed.