0
GSM-900 and GSM-1800 are used in most parts of the world: Europe, Middle East, Africa, Australia and most of Asia. In South and Central America the following countries use the following: : :* Costa Rica - GSM-1800 :* Brazil - GSM-850, 900 and 1800 :* Guatemala - GSM-850, GSM-900 and 1900 :* El Salvador - GSM-850, GSM-900 and 1900 GSM-900 uses 890-915 MHz to send information from the mobile station to the base station (uplink) and 935-960 MHz for the other direction (downlink), providing 124 RF channels (channel numbers 1 to 124) spaced at 200 kHz. Duplex spacing of 45 MHz is used. Guard bands 100 kHz wide are placed at either end of the range of frequencies[1]. : In some countries the GSM-900 band has been extended to cover a larger frequency range. This 'extended GSM', E-GSM, uses 880-915 MHz (uplink) and 925-960 MHz (downlink), adding 50 channels (channel numbers 975 to 1023 and 0) to the original GSM-900 band. The GSM specifications also describe 'railways GSM', GSM-R, which uses 876-915 MHz (uplink) and 921-960 MHz (downlink). Channel numbers 955 to 1023. GSM-R provides additional channels and specialized services for use by railway personnel. : All these variants are included in the GSM-900 specification. GSM-1800 uses 1710-1785 MHz to send information from the mobile station to the base tranceiver station (uplink) and 1805-1880 MHz for the other direction (downlink), providing 374 channels (channel numbers 512 to 885). Duplex spacing is 95 MHz. : GSM-1800 is also called DCS (Digital Cellular Service) in the United Kingdom, while being called PCS in Hong Kong[2] (not to mix up with GSM-1900 which is commonly called PCS in the rest of the world.)
