Equipment Chassis Definitions

'A' to 'E' Chassis Terms, 'F' to 'Z' Chassis Terms

AC: Abbreviation for Alternating Current.

Ambient Temperature. The surrounding temperature such as the temperature of air surrounding a conductor in a compartment or within a piece of equipment.

American Wire Gauge (AWG). The standards adopted in the United States for the measurement of wire sizes.

Assembly. A number of parts or subassemblies, or any combination thereof, joined together to perform a specific function.

ATR. Air Transport Rack. A chassis designed to comply to the military standard: MIL_PRF_85726B; Specification for Enclosure, Standard Avionics, Forced Air-Cooled.

Backplane. A Printed Wiring Board [PWB] consisting of some number of bussed connectors to accept daughter cards, which are then able into communicate over the backplane. Backplane Buses.

Bus. One or more conductors or optical fibers that serve as a common connection for a group of related devices. Chassis buses are normally copper traces on a Printed Circuit Board [PCB]. Also refer to Possible Networking Topologies.

Bus Bar. A heavy copper strap or bar used to connect several circuits together when a large current carrying capacity is required.

Cable. An assembly of one or more insulated conductors, or optical fibers, or a combination of both, within an enveloping jacket. Either a stranded conductor (single-conductor cable) or a combination of conductors insulated from one another (multiple conductor cable). Small sizes are commonly referred to as stranded wire or as cords. Wire and Cable Manufacturers

Cable Assembly. A cable that is ready for installation in specific applications and usually terminated with connectors. [Chassis Cable Assemblies]

Cable Harness. A group of wires or ribbons of wiring used to interconnect electronic systems and subsystems. How to Design a Cable Harness.

CAMAC. Computer Automated Measurement And Control. Another board/backplane interface bus system

Card Cage. A Card Cage has no enclosure at all and is just a frame [with card guides] to support the particular CCA form factor used.

Card Extender. A passive or active board that translates the signals on the backplane slot and extends them out to the front of the chassis by means of a circuit card assembly. The card extender accepts one circuit card to be plug into the front of the extender card, just as if it were being plugged into the backplane.

Commercial Gear. Equipment or parts that would normally operate from 0 to 70C. Non Military gear. Refer to the definition of COTS Equipment.

CompactPCI. Compact Peripheral Component Interface. An industrial version of the PCI standard [Peripheral Component Interface]. CompactPCI uses the Euro board format/size, but uses the same electrical standard as the consumer PCI interface bus.

Conduction Cooled. A board or chassis that uses heat conduction to draw heat away from sensitive electronics or other parts. A conduction cooled equipment chassis is normally fully enclosed with no fans or other openings for cool air. A conduction cooled board may or may not be fully enclosed, but will use large metal surfaces to draw heat away, sometimes into the card cage.

COTS. Commercial-Off-The-Shelf equipment that can be purchased through commercial retail or wholesale distributors as is (i.e., equipment that is available as a cataloged item) or with only minor modifications that does not alter its form, fit or functional characteristics. Detailed definition of COTS

COTS/NDI. Commercial Off-The-Shelf / Non-developmental Item.
A non-military or commercial product that has already been developed and is ready to be purchased under a published part number and requires no development time or additional NRE.

cPCI. See CompactPCI.

Crate. Another term for a chassis. Crate is used to describe a VXI chassis or crate.

Current Rating. The safe current-carrying capacity of a wire or cable on a continuous basis. See AWG

Derating. The process of reducing a particular characteristic so a device does not over-heat, as in Power, Temperature, or Current. See Component Derating Rules

Development Chassis A style of equipment chassis used in the development or debug stage of board or chassis design. In some cases a development chassis will be supplied with an open side or top to allow access to the cards inside the chassis

Next page of Equipment Chassis Terms

How To Specify a Equipment Chassis; Index page

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