Methods and apparatus for symbol timing recovery are provided. If a group of subscribers does not produce enough suitable answers, the present invention will then rebroadcast the inquiry to another group of subscribers. Determination then occurs according to the first comparative value and second comparative value as to whether the first output pin of the first power circuit breaker and the second output switch of the second power circuit breaker are contacted to each other. Furthermore, the optical disk player has the guide unit which is provided in a disk loading part.