Abstract: In a system for transmitting data, having a transmitting station and at least one receiving station, data is transmitted in packets of a first type, including a first data type identifier and data, and a second data type identifier, indicative of the type or nature of the data, is transmitted in a packet of a second type, including a further first data type identifier and the second data type identifier, wherein the first data type identifier and further first data type identifier are provided for linking the second data type identifier to the data. As the length of the first data type identifier is shorter than the length of the second data type identifier, the efficiency of the packets of the first type is improved in comparison with a system which only transmits packets of a first type, including the second data type identifier and the data. The invention is especially useful in RDS, wherein the packet of the first type is a version A group and a packet of the second type is a version B group.