a base station for mobile radio telecommunications systems comprises a radio frame set , an amplifier frame and an antenna interface frame connected to transmit and receive antennas . the radio frame set comprises a radio channel frame including a radio control complex , a plurality of radio channel units and a plurality of digital interface circuits for interconnecting the base station to a remote mobile telephone switching office . a time division multiplexed bus , connected to the radio control complex , the radio channel units and the interface circuits , is used for selectively connecting , under the control of the radio control complex , any radio channel unit to any digital interface circuit . such a radio channel arrangement is capable of handling analog , as well as , digital radio channel units while exhibiting greater capacity , easier maintenance and upgrade , and substantially increased flexibility .