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an attachment on honing and lapping machines for fine finishing (grinding and lapping) of surfaces. External cylindrical surfaces are finished using laps constructed in the form of rings with an adjustable longitudinal slit and a screw for regulating dimensions; the length of the lap should not be less than the diameter of the workpiece. Laps for grinding holes are constructed in the form of thin-walled cylinders with adjustable slits. Disk laps with grooves placed longitudinally and transversely at intervals of 12–15 mm are used for preliminary grinding of flat surfaces, and laps without grooves are used for the final finishing. For gear finishing, the laps used are also constructed in the form of gear wheels. Laps are made of cast iron, steel, copper, brass, and other materials. As a rule, the material from which the lap is made must be softer than the workpiece material.
LAP(1) (Link Access Protocol) The data link protocol in an AppleTalk network. Support for the various data link types were known as ELAP (Ethernet LAP), TLAP (Token Ring LAP), FLAP (FDDI LAP) and LLAP (LocalTalk LAP).
(2) (Link Access Procedure) An ITU family of data link protocols that are subsets of HDLC, which was derived from IBM's SDLC protocol. See HDLC.
LAP-B (LAP - Balanced)
Used in X.25 networks. Multilink Procedure (MLP) is a LAP-B extension that supports multiple, simultaneous links for increased throughput.
LAP-D (LAP for the D Channel)
Used for the D channel in ISDN networks defined in the ITU Q.920 and Q.921 recommendations. See ISDN.
LAP-M (LAP for Modems)
Used in V.42 modems. Although transmission between computer and modem is asynchronous, transmission between LAP-M modems is synchronous. See V.42.
LAP-X (LAP Half-Duplex)
Used in ship-to-shore transmission.