A washer used to obtain a 'finished' look. Usually used with oval head screws. Split Lock. The most common style of washer used to prevent nuts and bolts from backing out. External Tooth Lock. A washer with external 'teeth' Used to prevent nuts and bolts from backing out. Internal Tooth Lock. A washer with internal 'teeth' Used to prevent nuts and bolts from backing out.
(March 2009). A metropolitan area network (MAN) is a computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.istributed-queue dual-bus (DQDB) refers to the metropolitan area network standard for data communication specified in the IEEE 802.6 standard. With DQDB, networks can extend up to 20 miles (30 km) long and operate at speeds of 34â155 Mbit/s.
A local-area network (LAN) is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings, however, one LAN can be connected to other LANs over any distance via telephone lines and radio waves.A system of LANs connected in this way is called a wide-area network (WAN) . Most LANs connect workstations and personal computers.ypes of Local-Area Networks (LANs). There are many different types of LANs, with Ethernets being the most common for PCs. Most Apple Macintosh networks are based on Apple's AppleTalk network system, which is built into Macintosh computers.