hardware differences complete commonality was impossible to attain. IBM created two CUA standards, the Basic Interface for IBM 3270 and IBM 5250 terminals, and the Advanced Interface for so-called "intelligent workstations", or PCs. The keyboard was standardized to the Model M, 101 key, "AT Enhanced" keyboard layout. Common communications services (CCS) Common Communications Services defined the methods by which heterogeneous systems communicated. CCS depended on Advanced Program-to-Program Communications, also known as APPC or LU6.2, Systems Network Architecture (SNA) PU2.1 or Low Entry Networking for peer-to-peer networking, and SNA Management Services for network control. Three types of data links were supported: Synchronous Data Link Control (SDLC) high speed wide area networks X.25 packet-switched networks Token Ring local area networks (LAN) Application Services were provided by: CCS supported IBM 3270 data streams, mainly for existing devices Document Content Architecture specified a format for documents to be exchanged among different word processors and other software Intelligent Printer Data Stream (IPDS) was a page description language like Xerox Interpress or Adobe PostScript SNA Distribution Services (SNADS) for store and forward document transmission Document Interchange Architecture (DIA) for electronic mail Distributed Data Management Architecture (DDM) for file sharing and as the base architecture of DRDA Distributed Relational Database Architecture (DRDA) for sharing relational databases Common applications OfficeVision was the SAA-compliant successor to PROFS and AS/400 Office for "office automation". The AD/Cycle family of development tools was intended to simplify the development of SAA applications. References Further reading External links Systems Application Architecture Copyrights records, faqs.org Systems Application Architecture Systems Application Architecture