US Patent 7167764 Digital mixer and control method for digital mixer

There is provided a digital mixer including a plurality of functional blocks each having a CPU and a control program executed by the CPU which is capable of properly and easily controlling the version of the control program operated by the CPU of each functional block. When the power of the digital mixer is turned on, the respective versions of the functional blocks are acquired. Matching of the acquired versions of the functional blocks with the reference version is checked. When the checked versions of the functional blocks all match the reference version, the operation of the digital mixer is continued, and when at least one of the checked versions of the functional blocks mismatches the reference version, a warning is given to the user.