Part: ZN509 by GPS - 8pin DIP ADC Pinout Info, anyone?

Hi,

The GPS ZN509 is GEC Plessey 8-pin DIP ADC. I have searched the Net for data and the usual Datasheet Archive but cannot found any additional information. My only hope is someone have a databook that list this part.

Anyone has the pinout information or information on this chip?

Thanks.