X-25 is an ITU standard, well known and most widely used protocol established in 1976. The X-25 is subsequently revised in 1980, 1984, 1988, 1992 and 1993. The standard specifies an interface between a host system and a packet switching network. X-25 standard for packet switching is a lower three layer equivalent of the OSI model. This protocol based on a physical layer, a link layer, and packet layer. The data link layer of X-25 is link access procedure balanced (LAPB) using high level data link control (HDLC). HDLC is a bit oriented protocol based on the synchronous data link protocol (SDLC) established by IBM for Synchronous Network Architecture (SNA) networks. Fig. 11.9 shows the X-25 interface.

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DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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