Skip to main content


FC Lane Electronics glossary banner




Also known as 'backshells’ or ‘rear accessories’, accessories are components which are fitted onto the rear threads of connectors and make up the complete connector assembly. Also covered as a connector accessory are Cap and Cord and Cap and Chain.


A component which changes either the style or gender of a connector. For example, a between series adaptor changes the connector from one series interface to another. An in series adaptor changes the gender from male to female and vice versa. Between series and In series adaptors are typically used with BNC, TNC, N Type, SMA, SMB, SMC, MMCX, and MCX Coaxial connectors.

FC Lane Electronics is an authorised HUBER+SUHNER distributor and a stockist for the RF Adaptors that cover these applications.


Back mounted

Also known as rear mounted, these are connectors which have their mounting flange inside a box or panel.

Bayonet coupling

A coupling device which allows a plug to be mated to a receptacle using three evenly spaced pins. These connect with ramps that are machined into the coupling nut of the plug. Rotating the coupling nut enables coupling and decoupling.

FC Lane Electronics is an authorised stockist and distributor for the Weald Electronics LMH (MIL-DTL-26482) range of Bayonet locking connectors, and the reverse Bayonet locking MG series which is based on the MIL-DTL-5015 series of connectors. FC Lane Electronics also stocks and assembles the SOURIAU Connection Technologies MIL-DTL-D38999 series 1 connectors which are scoop proof, bayonet locking, crimp rear release connectors.
Blind mate

Blind mate connectors are usually rack and panel, such as Arinc 400 and 600, where the panel connector has a floating fixing, thus allowing the rack mounted connector to mate without any misalignment. The D connector family also have this float mount fixing mechanism.

BIN code

Stands for Basic Identification Number. Used to identify part numbers, these are comprised of coloured bands across the wire barrel end of a contact. BIN numbers correspond to one unique slash sheet, so help to identify the full M39029/XX-BIN part number.

Body material

Connector bodies (receptacles and plugs) can be made from either metal or man-made materials such as DAP, PTB, and Nylon. The most popular metals for circular and some rack and panel and D connectors are aluminium, stainless steel, nickel aluminium bronze, titanium, cold rolled steel, and brass.

Man-made composite is another material that is used for both circular and D-type connectors, where weight is a design criteria.

FC Lane Electronics Ltd is an authorised stockist, assembler, and distributor for SOURIAU Connection Technologies for the MIL-DTL-D38999 Series 3 and Series 1 ranges of connectors that utilise metal and composite body materials. FC Lane Electronics Ltd, is also an authorised stockist and distributor for Weald Electronics Ltd, Nicomatic, Positronic Industries, and ITW McMurdo, who offer a range of connector products that use man-made materials as their body material.


A part that is put onto a boot adaptor as well as Tynel ring and constant force spring braid trap adaptors, which environmentally seals a cable assembly and or helps to relieve strain.

FC Lane Electronics is an Authorised stockist and Distributor for Hellermann-Tyton who offer an extensive range of boots in multi branch, straight, and right angle forms.
Boot adaptor

A component which has one side threaded onto a connector plug or receptacle, and the other to accommodate a boot.


A flexible conductor made from a woven assembly of wires. Or a mesh of woven metallic material which provides an electrical screen to prevent the ingression of electrical magnetic interference.

Bulkhead connector

A connector that is fixed to a bulkhead either by a single jam nut or by four screws, and is hardwired on one side and has a mating free connector on the other side. A through bulkhead connector is mounted in the same way as a bulkhead connector, but has a plug/socket or socket/plug arrangement on either side and has mating free connectors on either side. The Bulkhead connectors are available from Weald Electronics LMF range.


The connecting of two or more electrical circuits.



Cable clamp

A device which is commonly known as a saddle clamp which, when attached to the rear threads of a plug or receptacle provides support for the cable or bundle of wires. It also offers strain relief which reduces shock and vibration.

Coaxial contact

A contact which has two conductive surfaces - a central contact and a coaxial sleeve.

Colour coding

A method for identifying extraction/contact insertion tools. The colours used indicate which tool should be used for inserting or extracting the relevant size of contacts.


Either a fixed receptacle, inline receptacle, through bulkhead or bulkhead receptacle, or a free plug that is used to connect or terminate the electrical conductors of a cable or wire. A connector offers a multitude of different terminations such as solder, crimp, screw, PCB, IDC, and fibre optic. Allows for continuation or termination of the conductors of a cable and provides a way to terminate or continue the conductors to a mating connector.


Either a socket or a pin, this is the conductive part of a connector which conducts electrical current.

Contact area

The area where pin and socket conductors are in contact which allows electric current to flow.

Contact arrangement

How contacts are arranged in a connector in terms of type, size, spacing, and number of contacts.

Contact engagement

Also known as ‘separation force’. How much force is required to separate or engage socket and pin contacts.

Contact resistance

The resistance on a pair of mated pin and socket contacts, which is measured in millivolt drop or ohms (resistance) across the contacts.

Contact retainer

A device, usually a metal clip or a plastic array, situated in the body of the connector insert, which secures the contact in the insert.

Contact retention

The measure of how much axial load a contact can take before it becomes separated from its retention mechanism within a connector insert.

Contact size

A number which describes the size or gauge of the end of a contact.

Contact shoulder

The flanged section of a contact, which dictates how far it can move into the insert, and stops it from being pushed out of the insert. An extra shoulder also allows space control for PCB mounted contacts.

Coupling nut/coupling ring

The part of a connector plug that can move and helps to couple, decouple, and lock a plug and its receptacle, either by a threaded coupling nut or a bayonet coupling nut, as well as the conventional push together action used for Edge Card and other like connectors, some of which use latches as locking mechanisms.


The compression of the barrel of a contact around a conductor, which enables an electrical connection.


The process by which a tool is used to fix a pin or socket contact to a conductor wire.

Crimp contact

A pin or socket contact with a hollow cylinder back section (wire barrel) into which a stripped conductor wire is inserted. The side walls of the barrel are uniformly compressed with a crimping tool in order to captivate the conductor. There is also a ‘witness hole’ to enable sight of the conductors and their position.

Crimp die

The part of the crimp tool that moulds the shape of the crimp on the wire barrel.

Crimp tool

A device that is used to perform crimping and holds the crimp die in position.



Depth of crimp

A measure of how far the crimp die indenter compresses the wire barrel.

D connector

An industry standard connector (MIL-DTL-24308) which comes in 9, 15, 25, 37, and 50 ways and has as standard solder, crimp IDC and PCB terminations which come in either straight or right angled variants. Locking mechanisms are usually jackscrews. Within the shell sizes, mixed signal, power, coax, and fibre contacts are also available.

FC Lane Electronics is an authorised stockist and distributor for Positronic Industries who offer an extensive range of D Connectors.

Die closure

A measure of the distance between the crimp die indenters when the crimp tool handle is at full closure. Often checked with a go/no go gauge.


A material that has electrical insulating properties.



Environmental sealing

A way to prevent contaminants such as moisture or dirt from entering a connector by using peripheral seals, interfacial seals, potting material, or gaskets.

Extraction tool

A tool that is used to extract contacts from a connector which can be colour coded plastic or metal.



Fibre optic

A glass cabling system that is high speed and low loss and is ideal for communications and the transmission of large bundles of data for applications such as Ethernet. Multimode fibre is ideal for short lengths whereas single mode is best used for longer lengths.

FC Lane Electronics is an authorised stockist and distributor for the SOURIAU Interconnection Technologies Elio series of fibre optic connectors, contacts and adaptors in both single mode and multimode, as well as cable assemblies to customer specification.
Filter contact

A contact which allows for the filtering of EMI signals, whilst maintaining its standard function.

Filter connector

A connector that uses filtered contact discs or capacitor arrays for filtering of EMI signals and doesn’t affect its standard function. Typical examples of filter connectors are the LMHF Range manufactured by Weald Electronics.

Fixed connector

A connector that is fixed to a box or panel by either a single hexagonal nut which is known as a jam nut or a circular nut. The square or oval flange connector is attached to a box or panel by 4 or 2 screws that either screw into a blind hole or fixing nuts.

Free connector

A connector that is connected to a cable by means of solder terminations, crimp terminations, or screw terminations, which then mates to a fixed connector, bulkhead connector, or a through bulkhead connector.

Free coupler

Also known as an inline receptacle which is cable mounted by means of solder terminations, crimp terminations, or screw terminations, and forms an in cable connection with a free connector which allows for the rerouting of internal cable runs by disconnecting one run and replacing it with another run.

Front mounting

A connector that has its mounting flange located outside of a panel or box. This is fixed to the panel or box by traditional screws and nuts or by screws and clinch nuts.

FC Lane Electronics is an authorised stockist, distributor, and assembler for short delivery of SOURIAU Interconnection products  and offers both D38999 series 3 square flange receptacles as well as the 8STA Motorsport receptacles with a clinch nut option.
Front release

Indicates the direction in which the contact removal tool should be inserted into the connector for contact removal. Front release connectors require that the tool is inserted into the front cavity of the connector. Contacts are inserted from the rear of the connector.




An elastomeric seal that is bonded to the connector rear. It has internal sealing barriers that seal the wire’s insulation, so that contaminants are unable to enter the connector rear.

Grounding fingers

Spring fingers which are part of a grounding spring, which is attached to the shell of a plug so that there is positive shell grounding when the contacts engage or disengage. They also improve RFI/EMI performance.



Hermetic connector

Hermetic connectors have traditionally been glass to metal seal and historically have been used to protect either a vacuum or fuel tanks. Almost any series of popular circular and D series connectors has a hermetic variant. FC Lane Electronics is an authorised stockist and distributor for SOURIAU Connection Technologies and Positronic Industries, who manufacture these products.

High current

A current range of 500 to 750 amps and in some cases higher rates can be achieved depending on the application.

FC Lane Electronics offers a range of three shell sizes in the D38999 Series 3 High Power range of connectors. There are two fixed styles and one plug available. The plug comes with either straight or right angle adaptors. This range is a part of FC Lane’s value added assembly program.

FC Lane Electronics is an authorised stockist, distributor, and assembler for short delivery of SOURIAU Interconnection Technologies products.

High density connector

A connector with closely arranged male or female contacts, but still providing optimal performance.

FC Lane Electronics Ltd offers high density connectors from the motorsport range of connectors from SOURIAU Interconnection Technologies.



The insulating connector core which helps to support, position, and enable separation for the connector contacts.

Insert orientation

A way of orientating the connector to prevent mismating of connectors with the same insert configuration. This is achieved by rotating the insert a specific number of degrees from the major keyway.

Insertion tool

A tool that is used to insert contacts into a connector which can be colour coded plastic or metal.

Inspection hole (witness hole)

A hole located at the bottom of a contact wire barrel, which provides a method for visually inspecting that the wire is inserted correctly before it is crimped.

Insulation jacket

Insulating material that is put around a cable or wire.


Found on the contact side of a mating plug, these two surfaces face each other and ‘interface’ when they are mated.

Interfacial seal

A seal over the whole area of the interface and around each contact of mating connectors. Commonly known as a ‘cork and bottle seal’, this is achieved by using a robust material with raised barriers around each cavity on the pin interface, which displaces into the recessed (chamfered) cavities on the socket interface.



Jacket insulation

The insulating material around a cable or wire.




The rectangular projecting part of a plug connector shell, which slides into the keyway or slot in the mating receptacle and allows for proper alignment of the two halves. Helps to ensure correct polarization.




A wire or material rope that is attached to a connector protection cap. Also, it is a durable wire that is attached to the plugs of certain connectors and provides easy separation and unmating with a pull on the wire (the lanyard).


Also called the turret head or positioner, this is attached to crimp tools with multiple locators to position variously sized contacts for crimping.




To join two connectors together.

Mated pair

A receptacle and plug that can be or are joined together.

Millivolt drop

The loss in voltage that occurs due to the resistance created by a crimp joint.



‘O’ ring

Also known as a peripheral seal, an ‘O’ ring is used around the edge of a connector shell to stop contaminants from entering. It works by being internally compressed between the receptacle and plug when they are mated. It can also be used as a seal between a panel and a connector.



Pin contact

A ‘male’ contact which connects with the ‘female’ socket contact.


The distance between the contacts which can be measured either as imperial or metric, with 0.1’’ or 2 mm being the standard. This criteria is usually applied to board to board, Edge Card, and board to cable connector applications.

FC Lane Electronics is an authorised stockist and distributor for Nicomatic, ITW McMurdo, and Weald Electronics, whose products address these applications.

The application of a thin layer of metal on connector contacts and shell. This helps to increase conductivity, stop corrosion, and facilitates simple easy soldering.


The unmounted connector of a mated pair, containing the nut for coupling/coupling ring, or latches which lock the connectors together.


The physical arrangement of keyways and rectangular keys to ensure correct mating. Also referred to as ‘keying’ or ‘clocking’, this ensures that there are no errors when mating identical connectors next to each other. This is achieved by either rotating the insert to different positions or utilising the keys in both the receptacle and the plug.


Also known as a ‘turret head’ or ‘locator’, this component is attached to a crimp tool with multiple locators in order to position differently sized contacts for crimping.


The final sealing of the back of a connector, once the wires have been inserted. Provides strain relief and prevents contaminants from entering.

Potting boot

This is a boot which is fitted onto the potting ring and threaded onto the back of the connector to provide strain relief and seal the connector from the environment.

Pull out force

The amount of force required to separate a wire from its crimped contact, or how much is required to pull it out from a connector.

Pull test

A test designed to determine the strength of a contact crimp joint.




The possible sizes of wire that can be accommodated by a contact wire barrel. Also the possible size of wire accommodated by a sealing grommet.

Rack and panel

Rack and panel connectors are usually rectangular and multipole. They have the options of signal, power, Quadrax, and fibre optic contacts depending on the series chosen.

FC Lane Electronics is an authorised stockist and distributor for both Positronic Industries and SOURIAU Interconnection Technologies, who both offer a comprehensive range of these products.

Radio frequency

Radio frequency connectors are categorised by their RF ranges and then by their contact size and resistance e.g. 50 ohm or 75 ohm. They either have bayonet or threaded coupling as standard, and the most common series are as follows: BNC, TNC, N, SMA, SMB, SMC, BNO, BNT, MCX, MMBX, and MMCX. There are also high voltage and quick fit versions such as the SHV series and the QMA and QN available.

FC Lane Electronics is an authorised HUBER+SUHNER distributor and stockist for the RF Connectors that cover these applications.

Rear accessories

Known as backshells or adaptors, these are components that screw onto accessory threads at the back of connectors.

Rear mounted

A connector that has its mounting flange mounted inside of a box or a panel.

Rear release

Indicates in which direction a contact removal tool should be inserted into a connector. For rear release connectors, the tool should be inserted from the rear of the connector.


The fixed or mounted member of a mated pair of connectors designed to be mounted to a box, panel or bulkhead.

Removal tool

A tool used to remove contacts from a connector which can be colour coded plastic or metal.



Safety wire

A wire that is threaded through drilled holes in the coupling nut/ring of a connector plug, which secures the wire to a bulkhead or panel, in order to stop the plug decoupling or coming loose from the receptacle when vibrating.

Scoop proof

Scoop proof designs feature a longer shell on the pin half (receptacle or plug) of a connector. This allows the contacts to be slightly recessed, so that they will not be damaged if the mating shell is ‘scooped’ into it during mating. Often used with small 22 size contacts, which can be prone to bending. FC Lane Electronics is an authorised stockist, distributor, and assembler for short delivery of SOURIAU Interconnection products and offers both D38999 series 1 and series 3 scoop proof connectors, either from stock or on a stock to build basis.

Screw thread

Coupling two circular connectors via a threaded mechanism is probably the most popular method of connector engagement today. The Tri-start threaded MIL DTL D38999 series 3 and the popular MIL DTL 5015 Weald LMJ series are two of the most used connector series in today’s market. These products are available from FC Lane Electronics Ltd who offer a stock to build program (five days for small quantities) as well as stock on the shelf for the SOURIAU Interconnection Technologies D38999 series 3.

FC Lane Electronics Ltd also stocks in depth the Weald LMJMIL-DTL-5015 standard connectors.

Sealing plug

A small plug which inserts into a connector’s rear grommet to seal and stop contaminants entering any unwired cavities. A typical part number is MS27488222.

Selective plating

The act of plating particular areas of contacts which are most susceptible to wear, usually the tip to increase number of mating cycles. Palladium plating is the norm for this.

Service rating

The maximum amount of current or voltage that a connector can carry for a sustained period.


A connector’s outer case that contains the dielectric contacts and insert.

Shielded contact

A contact that is shielded from EMI/RFI signals by using one or more protective outer conductors. In general, these are not matched with the impedance of the cable that they terminate.

Socket contact

A contact which has an engaging end that is designed to accept a pin contact.

Solder bucket

The rear part of the contact that has the facility to accept a wire that is terminated by a solder joint.

FC Lane Electronics is an authorised stockist and distributor for the Weald Electronics LMH (MIL-DTL- 26482) range of bayonet locking connectors and the reverse bayonet locking MG series which is based on the MIL-DTL-5015 series of connectors, as well as the LMJ series based on the MIL-DTL- 5015 range of threaded coupling connectors, all of which employ the solder bucket wire termination.

Solder contact

A socket or pin contact which accepts a conductor wire that is soldered onto the ‘solder cup’, instead of being crimped into the wire barrel.


A device which joins two or more conductor wires.


The act of removing the insulation from a conductor, most often when inserting a conductor into a contact’s wire barrel / solder cup for soldering / crimping.



Tensile test

A pulling test on a contact crimp joint, in order to determine its strength.

Test and measurement

FC Lane Electronics is an authorised stockist and distributor of the HUBER+SUHNER range of test and measurement products which includes precision adaptors, PIM adaptors, SucoForm, and SucoTest cable assemblies.

Thermocouple contact

A contact which is constructed of special material, is used in high temperature environments, and can measure temperature electrically. They are available in Weald Electronics LMF Range and Positronic D-connectors.

Threaded coupling

A method for coupling a mating connector pair by connecting the interior threads of a plug with the exterior threads of a receptacle.

Turret head

A device which is attached to a crimping tool that has various locators to help position different sized contacts when crimping.


If you still have questions about any technical terminology, or any of our products or services, please email us at or call us on +44 (0) 1403 790 661 for assistance.


Back to top