Cabling
Rack Unit
Also called: 1U, RU, rack elevation
The standard vertical increment of equipment rack space, 1.75 inches per U, used to plan how equipment stacks in a rack.
Rack elevations are drawn before equipment is ordered because U count is only part of the problem. Heat rises, so amplifiers belong above nothing sensitive; switches need front and rear clearance; UPS batteries go low for weight; and blank panels plus vents are what stop a sealed rack cooking its own contents.
Leave growth space deliberately. A rack filled to the last U guarantees the next addition gets mounted somewhere unserviceable, which is where documentation and airflow both start to fall apart.
Related terms
- IDF / MDF
- The hierarchy of network rooms in a building: the MDF is the main room where service enters and the core lives; IDFs are floor or zone closets that aggregate nearby horizontal runs back to it.
- UPS
- A battery-backed power source that keeps equipment running through outages and, just as importantly, filters the sags and surges that shorten hardware life.
- Matrix Switcher
- A device that routes any of several video inputs to any of several outputs independently, letting multiple sources appear on multiple displays at once.
- As-Built
- Documentation reflecting what was actually installed — final device locations, cable routes, labelling, IP addresses, and configuration — rather than what was originally drawn.
More Cabling terms
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