Switching means of a satellite has a first set of switches for receiving respective channel slots of de-multiplexed narrow band channels. The set of switches may be made up of four position switches 5 1 , 5 2 etc. Switch 5 2 may be connected straight through, or to the straight through positions of switches 5 1 and or 5 3 via interswitch connections. The same is possible with the second set of switches 6. A wide selection of the possible frequency slots is possible (for example eight out of sixteen) to allow routing among the amplifiers 9, 10, some of which are designated as redundant.