1.27mm (0.05") pitch. So-called because it was developed to be half the pitch of a 2.54mm (0.1") pitch connector, which was a very common and popular size.

A declaration that states that the plastic has no Halogen compounds (normally Chlorine or Bromine) as part of its composition. Chlorine and Bromine are used in various Flame Retardants, and are not uncommon in many plastics used in electronics.

A passive cooling device designed to sit above a source of heat in a circuit, that vastly maximizes the amount of surface to dissipate heat. Typically aluminium (which is a good conductor of heat), with many channels and vanes machined into a block. Most engineers will be familiar with the heat sinks in personal computers that are mounted on top of the main processing IC.

A type of rubber tubing that contracts when heat is applied. Can be used for covering exposed conductors or cable joints, for keeping multiple cables bundled together, or just for labelling/identification purposes. Also available in profiled shapes, known as boots.

A connector that includes a higher number of contacts in a set space. There is no exact definition for the number of contacts with a space that makes it high density - different manufacturers will use the term differently, partly depending on their existing range. For instance, a manufacturer selling connectors with pitches from 10mm down to 3mm might call the 3mm high density - but for a manufacturer selling from 2.54mm down to 0.5mm, the 1mm might be high density.

Connectors designed to handle high data-rates of multiple gigahertz (GHz). May also include dedicated ground planes or power planes. There is no set definition for this term, any manufacturer can use it if their product is proven to perform at high data-rates.

Connectors built to withstand high performance levels of vibration, shock and operating temperature range (and other robust or durable requirements). Generally specified in markets such as Aerospace, Defense, Motorsport, and high-end Industrial.

The amount of force that would need to be exceeded to separate two mated contacts or connectors. This force does not include anything contributed by mechanical fixings - it is purely to overcome the spring forces keeping the connection point mated. Is also referred to as Withdrawal Force - although some specifications may quote both, often there is very little difference.

See Backshells

A connector orientation - the mating face of the connector is at 90 degrees or right angles to the PCB where the connector is mounted. Called Horizontal because the housing lies horizontally flat along the PCB.

Connectors specially designed for hot-pluggable applications generally have the four corner ground pins longer than the rest, to ensure ground connection is made before any live electrical connections are mated. See Sequencing.

The amount of water vapor in the air. Connectors and other electrical devices normally have a humidity resistance rating, which is defined as a maximum amount of time in a certain relative humidity percentage in which the device has been tested to still perform to its operating parameters.