When an algorithm bay is connected to a signal processing apparatus according to a first connection mode, a selector of the algorithm bay selects and sets a first function provided by a first function provider as the signal processing function of the signal processing apparatus. According to a second connection mode, the selector selects and sets a second function provided by a second function provider as the signal processing function Also, a first information provider of an algorithm bay may supply a signal indicating first information to a signal processor of a signal processing apparatus via a wired interface of the algorithm bay, a wired connection, and a wired interface of the signal processing apparatus. Similarly, a second information provider of the algorithm bay supplies a signal indicating second information for changing the signal processing function of the signal processor to the signal processor.