Ontwikkeling VME Ethernet Kaart (Developing VME Ethernet Card)

摘要

The X.25 UNICOM (Universal Communication Module) is a single-board microprocessor with two serial channels, one for connecting to the X.25 and one for the user. The user channel provides the OSI X.213 network service. In a design modification, the serial user channel was replaced by a dual-ported RAM and a VME-bus interface, and the UNICOM card format was altered to VME format. On this X.25 VME card are a 68000 Motorola microprocessor, some peripheral elements, and an X.25 Western Digital Controller (WD2511, controlling the entire LAP.b protocol). The thesis describes development of a Local Area Network card, starting from an X.25-VME card. The LAP.b protocol is replaced by an Ethernet protocol. In conjunction with the X.25 Packet Level protocol (X.25-PLP) this LAN card provides network service, and has the potential for providing speech over the Ethernet.