Abstract: Collator apparatus and methods for preventing incorrect operations of first and second machines such as a combination scale and a packaging machine which are to be used together to process the same type of product. The first machine has a first memory for storing operation condition data, each with a different data number (address), and has an associated first memory control. The second machine has a second memory for storing other operation condition data, each with a different data number, and an associated second memory control. The first memory control of the first machine is caused to generate a specified one of the data numbers of the first memory. The collator apparatus sends a request signal to the second memory control of the second machine to cause the second memory control to generate a data number of the second memory, which data number corresponds to the specified one by a predetermined relationship in the absence or malfunction.