1U
)Also referred to as 1RU, although RU is not technically correct.
U is the standard unit of measure for designating the vertical usable space, or height of racks (metal frame designed to hold hardware devices) and cabinets (enclosures with one or more doors). This unit of measurement refers to the space between shelves on a rack. 1U is equal to 1.75 inches. For example, a rack designated as 20U, has 20 rack spaces for equipment and has 35 (20 x 1.75.) inches of vertical usable space. Rack and cabinet spaces and the equipment which fit into them are all measured in U.
Image Source: Site Planning Guide for Entry-Level Servers
Read Also:
- 1xRTT
Short for single carrier (1x) radio transmission technology, a 3G wireless technology based on the CDMA platform. 1xRTT has the capability of providing ISDN-like speeds of up to 144 Kbps. 1xRTT is also referred to as CDMA2000.
- 24-7
In computer and Internet slang, 24-7 is commonly used to describe an Internet connection that is available 24 hours a day, seven days a week. 24-7 connections usually refer to broadband Internet connections such as DSL or cable. Also called always on. See “Types of Internet Connections” in the Quick Reference section of
- 2B1Q
Short for 2 Binary 1 Quaternary, a full duplex physical layer encoding method used in ISDN and other digital communication technologies. In 2B1Q, two binary bits are encoded into one quaternary signal, doubling the effectiveness of transmission.
- 2-205 rule
A rule for the configuration of 100Base-T, or Fast Ethernet, networks. According to the rule, the maximum network distance, or network diameter, of two non-stackable network hubs connected by copper cabling cannot exceed 205 meters (approx. 672 feet). Also referred to as the Fast Ethernet rule.
- 2:2 pulldown
Also called telecine, 2:2 pulldown is the process used to convert motion picture movie film to PAL interlaced video. Each frame of film is converted into two interlaced video frames. This is the process that enables you to view captured motion pictures on standard televisions and video electronics. See anamorphic widescreen.