The present document is the baseline specification for the provision of the interaction channel for digital terrestrial television distribution system@ DVB-T defined in the EN 300 744 standard [1]. The present document: ? gives a general description of the baseline system for interactive digital terrestrial TV; ? specifies the channel coding/modulation; specifies the medium access control protocol; ? provides guidelines on the radio frequency spectrum management. The purpose of the MAC section is to redefine a set of MAC messages based on the DVB-RCCL MAC message set@ adapted to suit the specific characteristics of the physical layer of the DVB-RCT specification. The solution provided in the present document for return channels through terrestrial broadcast systems is part of a wider set of alternatives for implementing interactive services for DVB systems.