Certain features relate to a digital multichannel interface between a base station and a repeater in a telecommunications system, such as a distributed antenna system. The digital multichannel interface can provide streams of I/Q samples that carry information from multiple carriers of a wideband communications signal as well as semi-static control information for the telecommunications system. The digital multichannel interface can also transport frame timing information between the base station and the repeater. The frame timing information can maintain synchronization between the uplink transmit frames carrying uplink I/Q samples and the downlink transmit frames carrying downlink I/Q samples.