A method of transmitting data allows flow control information to be transmitted with the user data over a synchronous bus. A channel is defined, identifying the source and at least one sink, and this includes the definition of a transport profile, indicating a flow control requirement for the data. Data is then transmitted from the source over the bus in at least one data time slot (30) and, if indicated by the transport profile, flow control information is also transmitted from the source over the bus in at least one flow control time slot (20) associated with the data time slot.
