(SPX) A transport layerprotocol built on top of IPX. SPX is used in Novell NetWare systems for communications in client/server {application programs}, e.g. {BTRIEVE} ({ISAM} manager). SPX is not used for connections to the file server itself this uses NCP. It has been extended as SPX-II. SPX/IPX perform equivalent functions to TCP/IP. . [Better reference?] (1999-05-27)