Which source of product codes relies on the manufacturer's system?

Manufacturers' codes are specifically developed and used by the manufacturers themselves to identify products within their system. These codes are often unique to the manufacturer and can include information such as the product type, production batch, and other relevant identifiers. This reliance on the manufacturer's system ensures consistency and accuracy in product identification from the source where it is created.

In contrast, the other options relate to coding systems that are not exclusively controlled or defined by the manufacturer. Customer codes, for instance, may vary from one customer to another based on their specific requirements and tracking systems. A company's own coding system would be specific to that particular organization and not universally applicable. Similarly, an industry standard coding system is designed to create a common reference across different manufacturers and users, fulfilling collective needs rather than the exclusive needs of a single manufacturer.