The PD75P316B is a product of the PD75316B with its built-in ROM having been replaced with the onetime PROM. It is most suitable for test production during system development and for production in small amounts since it can operate under the same supply voltage as mask products. The one-time PROM product is capable of writing only once and is effective for production of many kinds of sets in small quantities and early startup. The EPROM product allows programs to be written and rewritten, making it ideal for system evaluation. Functions are described in detail in the following User'S Manual, which should be read when carrying out design work.