An interface device, such as for a System-on-Chip (SoC) bus, transfers data from an input queue through an output to a target. The interface device includes a buffer network for buffering input data when the target is not available for receiving the data. A multiplexer switches between a first operating condition for directing to the target the data from the input queue, and a second operating condition for directing to the target the buffered data from the buffer network. A finite-state machine selectively switches the multiplexer between the first operating condition and the second operating condition based on an acknowledgement signal received from the target. This indicates the availability of the target for receiving the data.