Abstract: A network adapter and wiring scheme makes use of existing plain old telephone service (POTS) wiring to provide support between analog devices within the subscriber premise and an Integrated Digital Service Network (ISDN). Moreover, the network adapter and wiring scheme provides further support between digital devices within the premise and the ISDN while concurrently supporting analog devices.

Abstract: A special purpose communications protocol processor (CPP) provides more efficient processing of layered communications protocols--e.g. SNA (Systems Network Architecture) and OSI (Open Systems Interconnection)--than contemporary general purpose processors, permitting hitherto unavailable operations relative to high speed communication links. The CPP contains special-purpose circuits dedicated to quick performance (e.g. single machine cycle execution) of functions needed to process header and frame information, such functions and information being of the sort repeatedly encountered in all protocol layers, and uses instructions architected to operate these circuits. The header processing functions given special treatment in this manner include priority branch determination functions, register bit reshaping (rearranging) functions, and instruction address processing functions.