Lasing of an optical channel at a particular wavelength is substantially prevented in an optical ring network by automatically verifying the presence of a break, e. The method includes selectively storing a schedule state to a storage medium based on a latency attribute associated with the schedule. The input interface is configured to receive a color graphic array video signal. Data output from the information processing units are stored in parallel in a register on a unit length basis for serial transmission. Furthermore, the reproduction-dedicated layer contains CSS encryption data and an identifier indicating that it is dedicated for reproduction.