[emeritus]

It always seemed to be difficult to get info from Plessey Semiconductors, even if you worked for other Plessey divisions! Plessey Semiconductors used to do a considerable business as a foundry for third party designs. For some customers they simply supplied packaged, untested, ICs from masks provided by the customer, and so did not necessarily know what functions a chip was performing. The families of ICs used in the projects I was involved in were for various defence projects with high degrees of security classification, so no info would be publicly available about them.