This glossary defines key terms related to the 2.0 mm ERmet Hard Metric Connector System and general electronics terminology.
Electromagnetic interference.
To incise an area of a printed wiring board by immersing the board in an acid batch. The parts of the board not covered with an acid-resistant coating will be eroded.
The particular compliant section design utilized by ERNI for many DIN 41612 and D-Sub pressfit contacts. This coined, elastic section provides a very reliable gas tight connection with the plated through hole in the backplane or daughter card.
This is the compliant section design utilized by ERNI for our 2 mm ERmet pressfit contacts. This pierced and coined elastic section provides a very reliable gas light connection with the plated through hole in the backplane or daughter card.
A printed circuit board that plugs into a slot position of a backplane. Function cards can be custom designed by the user or bought as a standard off-the-shelf item. A series of these cards can make up a system or subsystem to run machinery or many other electronic functions.
An abbreviation for ground. The potential referred to as zero volts. An electrical connection between any circuit and the reference potential.
The pair of traces which surround a third conductor to minimize crosstalk.
A common conductive surface that receives and returns power/signal transmissions.
A conductor (usually a plane), at some reference potential (e.g. zero volts), which surrounds some other insulated conductor.
Global specification that governs 2mm Hard Metric equipment practices.
Defines a basic pitch of 0.5 mm, with n x 0.5 mm as the multiple pitch, and a system unit of 25 mm. This, in turn, relates to Hard Metric Equipment practices, IEE 1301 and DIN 433586, used for mechanical arrangement of electrical/electronic equipment, including associated board layout and connections.
Abbreviation for input/output.
Abbreviation for the Institute of Electronic and Electrical Engineers.
Resistance of a signal line measured in ohms. One of the important electrical characteristics of a backplane, impedance is determined by the physical dimensions of trace width, dielectric thickness, dielectric constant, and so forth.
The ratio of the voltage to the rate of change of current in a circuit (V/AL).
A plane in a printed wiring board which has a copper covering in some specified pattern (e.g. plane, traces and pads).
(1) The name given to a signal line referenced above a single ground plane. (2) The outer etched portion of a backplane transmission line.
The current, voltage, power, or signal which a circuit or device delivers. Terminals where a device delivers its information.
The circular area that commits a hole to an uncommitted layer or trace.
(Personal Computer Memory Card International Association). A standard for removable cards.
The PCI Industrial Computer Manufacturers Group is a trade association that has developed a number of specifications related to personal computer architectures and CompactPCI. Their web address is http://www.picmg.org.
A term used to describe the actual connections for each pin of a connector on a printed wiring board.
A hole in a printed wiring board, used to commit external or internal layers to one another produced by electro deposition of a conductive pattern.
To form a thin, adherent layer of material (usually metal) on an object.
PCI mezzanine card interface, defined by IEEE 1336
An interference connection used in the assembly process to eliminate the need for solder to make the electrical connection.
(1) Referred to as tpd, commonly expressed in nanoseconds per inch (ns/in). It is the time required for a pulse to travel through a transmission line system. (2) The time it takes for a signal to spread or distribute across an entire circuit.
(See Subrack) - A sheet metal assembly that is made up of mounting bars and side plates to which a backplane can be mounted and printed wiring boards can be inserted.
The opposition that a material or device offers to the flow of current, equal to the voltage drop across the element, divided by the current through the element.
Radio Frequency Interference.
Often designated as tr, in picoseconds. It is the time it takes the signal to transition from 10 percent to 90 percent of its' final value.
The time difference between the arrival of two related signals, often due to differences in their propagation paths.
A male connector body designed to fit over the extended tails of a long tail connector which allows a female connector to be mated from the rear side for midplane or rear I/O applications.
An electrical pulse which conducts across a backplane.
A term used to specify the length of the pins on any connector. Typically the pins will protrude through the printed wiring board. Extended pins extend much further.
The coating on a printed wiring board, placed there for protection. Also aids in assembly and soldering.
A popular mathematical representation of high frequency characteristics of a component such as a connector utilized for signal integrity measurement and analytical techniques. Often utilized in applications where SPICE modeling is not practical.
Software Program for Integrated Circuit Emulation. One of several computer based techniques for simulating the electrical performance of various circuit components such as connectors and integrated circuits within a actual or theoretical circuit configuration.
(1) The name given to a signal, referenced between two ground planes, at a defined spacing. (2) The etched portion of a backplane transmission line that is between two ground planes in a multilayer printed circuit board.
A card cage assembly, usually designed to support a backplane, card guides and daughter cards.
A line or trace is considered terminated at any point there is a resistor connected to it.
The permissible variations in the dimensions of manufactured parts or electrical components.
The conductor that physically joins two or more points on a printed wiring board.
A perpendicular board assembly used to plug into extended connector terminals on the rear side of the backplane as in mid plane chassis designs or when it is not desirable to utilize cables to interface to the rear connectors.
A line is referred to as a transmission line when its capacitance and inductance are distributed over the line. Such a line will convey a signal without distortion and will appear as a purely resistive input impedance.
Transistor-Transistor Logic. A logic circuit containing two transistors, for driving large output capacitances at high speed.
A printed wiring board with only the outer layers containing traces. This product may or may not contain plated through holes.
An EIA unit of measurement equal to 1.75" for equipment racks.
Any bussed trace that is not connected.
Typically, the collector voltage level for a transistor. The designation of the primary voltage level on a printed wiring board, usually at the potential of +5 volts.
A plated through-hole that is there for the sole purpose of conducting a signal trace or potential from one layer of the printed wiring board to another.
The VME International Trade Association is a trade association that supports VME and other imbedded industry computer manufacturers. It also supports an ANSI recognized standards producing organization, the VSO. VITAs web address is http://www.vita.com.
The initials for the backplane bus architecture known as Versa Module Europa.
The electromotive force determined by the potential difference between two conductors, measured in volts.
The VITA Standards Organization. An ANSI recognized standards producing organization concerned with computer architectures. See VITA.
A termination technique, used mainly to prototype computers and computer systems, identifiable by the presence of elongated pins to which signal wires and voltage and ground connections can be created.
The circular area around a hole that is measured by the difference between the radius of the wall of the hole, subtracted from the radius of the clearance or pad around the hole.
Abbreviation for American National Standards Institute.
The representation of the electrical layout of a printed circuit on a transparency.
When a signal travels along the bus, its amplitude decreases due to energy losses from heating, radiation, and so forth.
Abbreviation for American Wire Gage. A particular series of specified diameters and thicknesses established as a standard in the U.S.A. and used for nonferrous sheets, rods and wires.
(1) A wiring board usually constructed as a printed circuit, used in micro and mini computers to provide the required connections between logic, memory and I/O modules. (2) A two-sided or multilayer printed circuit board into which function cards can be plugged. The backplane transfers signals between the function cards. Mounted on the component side of the backplane are connectors into which function cards can be plugged. On the solder side of the backplane are termination points (studs, power bugs, quick disconnects) for the distribution of power and ground.
Bell Research Corporation, originally the research division for AT&T.
A circuit over which data or power is transmitted.
A set of rules governing the circuit design of a system such as: CompactPCI, VME, Multibus I, Multibus II and Q-Bus, to name a few.
Impedance is referred to as Zo, in ohms. It is the resistance seen by a digital signal and is measured between the signal line and the reference plane. This impedance is a function of the signal line geometry and is independent of the line length. Impedance is the key parameter which interrelates all performance characteristics of the backpanel, including delay, noise and distributed capacitance.
A bus structure developed by the PICMG based on the desktop PCI architecture.
A pin whose physical structure is designed to elastically deform upon insertion into a hole.
The side of a printed wiring board or backplane into which connectors, resistors, capacitors and so forth are inserted.
The ratio of the number of components to a given area of a board.
The distance between adjacent traces on a printed wiring board.
The width of a given trace.
(1) The interaction observed due to electromagnetic coupling of adjacent conductors. (2) A false signal picked up by a signal line (in an inductive manner) from an adjacent signal line.
The net transfer of electric charge, per unit time, along a conductor. An amount equal to the voltage/resistance and measured in Amperes.
A bus structure used specifically to transmit data, or bits of information.
Stamped or printed on a component the week and year the component was made (i.e. 9023 is the 23rd week of the year 1990, or June 3rd-7th, 1990).
Same as function card or function board.
To physically remove material from an area of a board so as to break the electrical connection to that plane.
To prevent transfer or feedback of energy from one circuit to another.
(1) A material which is an electrical insulator that can sustain an electrical field with minimum power loss. (2) Any insulating medium that intervenes between two conductors.
The property of a material that governs the propagation delay of a signal it surrounds, denoted by r.
(1) Stands for Deutsches Institut fur Normung, a German organization which established many mechanical specifications for connectors and packaging. (2) Vernacular for Standard European connector having 96 pins arranged in 3 rows of 32 pins each. The rows are labeled A, B, C.
Abbreviation for Dual-In-line Package. A device that has two rows or parallel pins. Usually the pins in each row are on .100" centers.
An individual resistor, as opposed to a resistor network.
Distributed capacitance, referred to as C, is the amount of capacitance per unit length of a signal line.
Abbreviation for Emitter-Coupled-Logic, a form of current-mode logic in which the emitters of two transistors are connected to a current carrying resistor in such a way that only one will turn on at time.
The Enterprise Computer Telephony Forum is a trade association that has developed a number of specifications related to computer telephony. Their web address is: http://www.ectf.org.
Electronics Industry Association.
| Term | Definition |
|---|---|
| EMI | Electromagnetic interference. |
| Etch | To incise an area of a printed wiring board by immersing the board in an acid batch. The parts of the board not covered with an acid-resistant coating will be eroded. |
| ERNIPRESS | The particular compliant section design utilized by ERNI for many DIN 41612 and D-Sub pressfit contacts. This coined, elastic section provides a very reliable gas tight connection with the plated through hole in the backplane or daughter card. |
| Eye of the Needle | This is the compliant section design utilized by ERNI for our 2 mm ERmet pressfit contacts. This pierced and coined elastic section provides a very reliable gas light connection with the plated through hole in the backplane or daughter card. |
| Function Card | A printed circuit board that plugs into a slot position of a backplane. Function cards can be custom designed by the user or bought as a standard off-the-shelf item. A series of these cards can make up a system or subsystem to run machinery or many other electronic functions. |
| GND | An abbreviation for ground. The potential referred to as zero volts. An electrical connection between any circuit and the reference potential. |
| Ground Guard | The pair of traces which surround a third conductor to minimize crosstalk. |
| Ground Plane | A common conductive surface that receives and returns power/signal transmissions. |
| Ground Shield | A conductor (usually a plane), at some reference potential (e.g. zero volts), which surrounds some other insulated conductor. |
| IEC 61076-4-101 | Global specification that governs 2mm Hard Metric equipment practices. |
| IEC 917 (DIN 43355) | Defines a basic pitch of 0.5 mm, with n x 0.5 mm as the multiple pitch, and a system unit of 25 mm. This, in turn, relates to Hard Metric Equipment practices, IEE 1301 and DIN 433586, used for mechanical arrangement of electrical/electronic equipment, including associated board layout and connections. |
| I/O | Abbreviation for input/output. |
| IEEE | Abbreviation for the Institute of Electronic and Electrical Engineers. |
| Impedance | Resistance of a signal line measured in ohms. One of the important electrical characteristics of a backplane, impedance is determined by the physical dimensions of trace width, dielectric thickness, dielectric constant, and so forth. |
| Inductance | The ratio of the voltage to the rate of change of current in a circuit (V/AL). |
| Layer | A plane in a printed wiring board which has a copper covering in some specified pattern (e.g. plane, traces and pads). |
| Microstrip | (1) The name given to a signal line referenced above a single ground plane. (2) The outer etched portion of a backplane transmission line. |
| Output | The current, voltage, power, or signal which a circuit or device delivers. Terminals where a device delivers its information. |
| Pad | The circular area that commits a hole to an uncommitted layer or trace. |
| PCMCIA | (Personal Computer Memory Card International Association). A standard for removable cards. |
| PICMG | The PCI Industrial Computer Manufacturers Group is a trade association that has developed a number of specifications related to personal computer architectures and CompactPCI. Their web address is http://www.picmg.org. |
| Pin-out | A term used to describe the actual connections for each pin of a connector on a printed wiring board. |
| Plated through-hole | A hole in a printed wiring board, used to commit external or internal layers to one another produced by electro deposition of a conductive pattern. |
| Plating | To form a thin, adherent layer of material (usually metal) on an object. |
| PMC | PCI mezzanine card interface, defined by IEEE 1336 |
| Pressfit | An interference connection used in the assembly process to eliminate the need for solder to make the electrical connection. |
| Propagation Delay | (1) Referred to as tpd, commonly expressed in nanoseconds per inch (ns/in). It is the time required for a pulse to travel through a transmission line system. (2) The time it takes for a signal to spread or distribute across an entire circuit. |
| Rack | (See Subrack) - A sheet metal assembly that is made up of mounting bars and side plates to which a backplane can be mounted and printed wiring boards can be inserted. |
| Resistance | The opposition that a material or device offers to the flow of current, equal to the voltage drop across the element, divided by the current through the element. |
| RFI | Radio Frequency Interference. |
| Risetime | Often designated as tr, in picoseconds. It is the time it takes the signal to transition from 10 percent to 90 percent of its' final value. |
| Skew | The time difference between the arrival of two related signals, often due to differences in their propagation paths. |
| Shroud | A male connector body designed to fit over the extended tails of a long tail connector which allows a female connector to be mated from the rear side for midplane or rear I/O applications. |
| Signal | An electrical pulse which conducts across a backplane. |
| Solder or Extended Tail | A term used to specify the length of the pins on any connector. Typically the pins will protrude through the printed wiring board. Extended pins extend much further. |
| Solder Mask | The coating on a printed wiring board, placed there for protection. Also aids in assembly and soldering. |
| S-Parameters | A popular mathematical representation of high frequency characteristics of a component such as a connector utilized for signal integrity measurement and analytical techniques. Often utilized in applications where SPICE modeling is not practical. |
| SPICE | Software Program for Integrated Circuit Emulation. One of several computer based techniques for simulating the electrical performance of various circuit components such as connectors and integrated circuits within a actual or theoretical circuit configuration. |
| Stripline | (1) The name given to a signal, referenced between two ground planes, at a defined spacing. (2) The etched portion of a backplane transmission line that is between two ground planes in a multilayer printed circuit board. |
| Subrack | A card cage assembly, usually designed to support a backplane, card guides and daughter cards. |
| Terminated | A line or trace is considered terminated at any point there is a resistor connected to it. |
| Tolerance | The permissible variations in the dimensions of manufactured parts or electrical components. |
| Trace | The conductor that physically joins two or more points on a printed wiring board. |
| Transition Board | A perpendicular board assembly used to plug into extended connector terminals on the rear side of the backplane as in mid plane chassis designs or when it is not desirable to utilize cables to interface to the rear connectors. |
| Transmission Line | A line is referred to as a transmission line when its capacitance and inductance are distributed over the line. Such a line will convey a signal without distortion and will appear as a purely resistive input impedance. |
| TTL | Transistor-Transistor Logic. A logic circuit containing two transistors, for driving large output capacitances at high speed. |
| Two Sided | A printed wiring board with only the outer layers containing traces. This product may or may not contain plated through holes. |
| U | An EIA unit of measurement equal to 1.75" for equipment racks. |
| Un-terminated | Any bussed trace that is not connected. |
| Vcc | Typically, the collector voltage level for a transistor. The designation of the primary voltage level on a printed wiring board, usually at the potential of +5 volts. |
| Via | A plated through-hole that is there for the sole purpose of conducting a signal trace or potential from one layer of the printed wiring board to another. |
| VITA | The VME International Trade Association is a trade association that supports VME and other imbedded industry computer manufacturers. It also supports an ANSI recognized standards producing organization, the VSO. VITAs web address is http://www.vita.com. |
| VME | The initials for the backplane bus architecture known as Versa Module Europa. |
| Voltage | The electromotive force determined by the potential difference between two conductors, measured in volts. |
| VSO | The VITA Standards Organization. An ANSI recognized standards producing organization concerned with computer architectures. See VITA. |
| Wirewrap | A termination technique, used mainly to prototype computers and computer systems, identifiable by the presence of elongated pins to which signal wires and voltage and ground connections can be created. |
| Annular Ring | The circular area around a hole that is measured by the difference between the radius of the wall of the hole, subtracted from the radius of the clearance or pad around the hole. |
| ANSI | Abbreviation for American National Standards Institute. |
| Artwork | The representation of the electrical layout of a printed circuit on a transparency. |
| Attenuation | When a signal travels along the bus, its amplitude decreases due to energy losses from heating, radiation, and so forth. |
| AWG | Abbreviation for American Wire Gage. A particular series of specified diameters and thicknesses established as a standard in the U.S.A. and used for nonferrous sheets, rods and wires. |
| Backplane | (1) A wiring board usually constructed as a printed circuit, used in micro and mini computers to provide the required connections between logic, memory and I/O modules. (2) A two-sided or multilayer printed circuit board into which function cards can be plugged. The backplane transfers signals between the function cards. Mounted on the component side of the backplane are connectors into which function cards can be plugged. On the solder side of the backplane are termination points (studs, power bugs, quick disconnects) for the distribution of power and ground. |
| Bellcore | Bell Research Corporation, originally the research division for AT&T. |
| Bus | A circuit over which data or power is transmitted. |
| Bus Structure | A set of rules governing the circuit design of a system such as: CompactPCI, VME, Multibus I, Multibus II and Q-Bus, to name a few. |
| Characteristic Impedance | Impedance is referred to as Zo, in ohms. It is the resistance seen by a digital signal and is measured between the signal line and the reference plane. This impedance is a function of the signal line geometry and is independent of the line length. Impedance is the key parameter which interrelates all performance characteristics of the backpanel, including delay, noise and distributed capacitance. |
| CompactPCI | A bus structure developed by the PICMG based on the desktop PCI architecture. |
| Compliant | A pin whose physical structure is designed to elastically deform upon insertion into a hole. |
| Component Side | The side of a printed wiring board or backplane into which connectors, resistors, capacitors and so forth are inserted. |
| Component Density | The ratio of the number of components to a given area of a board. |
| Conductor Spacing | The distance between adjacent traces on a printed wiring board. |
| Conductor Width | The width of a given trace. |
| Crosstalk | (1) The interaction observed due to electromagnetic coupling of adjacent conductors. (2) A false signal picked up by a signal line (in an inductive manner) from an adjacent signal line. |
| Current | The net transfer of electric charge, per unit time, along a conductor. An amount equal to the voltage/resistance and measured in Amperes. |
| Data Bus | A bus structure used specifically to transmit data, or bits of information. |
| Date Code | Stamped or printed on a component the week and year the component was made (i.e. 9023 is the 23rd week of the year 1990, or June 3rd-7th, 1990). |
| Daughter Card | Same as function card or function board. |
| Decommitted | To physically remove material from an area of a board so as to break the electrical connection to that plane. |
| Decouple | To prevent transfer or feedback of energy from one circuit to another. |
| Dielectric | (1) A material which is an electrical insulator that can sustain an electrical field with minimum power loss. (2) Any insulating medium that intervenes between two conductors. |
| Dielectric Constant | The property of a material that governs the propagation delay of a signal it surrounds, denoted by r. |
| DIN | (1) Stands for Deutsches Institut fur Normung, a German organization which established many mechanical specifications for connectors and packaging. (2) Vernacular for Standard European connector having 96 pins arranged in 3 rows of 32 pins each. The rows are labeled A, B, C. |
| DIP | Abbreviation for Dual-In-line Package. A device that has two rows or parallel pins. Usually the pins in each row are on .100" centers. |
| Discrete Resistor | An individual resistor, as opposed to a resistor network. |
| Distributed Capacitance | Distributed capacitance, referred to as C, is the amount of capacitance per unit length of a signal line. |
| ECL | Abbreviation for Emitter-Coupled-Logic, a form of current-mode logic in which the emitters of two transistors are connected to a current carrying resistor in such a way that only one will turn on at time. |
| ECTF | The Enterprise Computer Telephony Forum is a trade association that has developed a number of specifications related to computer telephony. Their web address is: http://www.ectf.org. |
| EIA | Electronics Industry Association. |
