IBM Corp and Nynex Corp are to participate in an Integrated Services Digital Network field trial due to start next April l988, the first ISDN trial involving IBM and a US carrier. The trial is intended to aid in development of international standards for ISDN network interfaces that connect communications nets to display terminals and other devices, and to improve understanding of the benefits of ISDN for user applications.The field trial will test network interfaces linking two Nynex locations, using an (Ericsson?) exchange in Nynex’s Network Services Development Center in New York City, and will include IBM’s Systems Network Ar-chitecture protocols, will use IBM-provided workstations and controllersequipped with experimental ISDN interface adaptors and will measure thebenefits of improved performance and switching capability on test versions of applications that are used by Nynex for internal data processing.