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Sheath:

The outer covering or jacket of a multi-conductor cable.

Shield:

In cables, a metallic layer placed around a conductor or group of conductors to prevent electrostatic or electromagnetic interference between the enclosed wire and external fields. See Braid.

Shield Effectiveness:

The ability of a shield to screen out undesirable signals and prevent leakage.

SI:

The standard international system of metric units of measurement.

Silica Glass (Fiber Optic):

Glass made mostly from silica (silicon dioxide, SiO2) used to make fibers.

Simplex Cable (Fiber Optic):

A single fiber cable.

Single Mode Fiber (Fiber Optic):

Abbreviated as SMF, a fiber having a small core diameter (approximately 9 microns) with a cladding having a refractive index very close to that of the core. Will transmit light in a single mode that enters at a narrow angle but will transmit over very wide bandwidths.

SMPTE:

An acronym for "Society of Motion Picture & Television Engineers," a USA standards organization.

Socket Contact:

A female contact designed to mate with a male contact. It is normally connected to the "live" side of a circuit.

Solder:

A metal or metal alloy, usually having a low melting point, used to join other metals having higher melting points than the solder.

Solder Cup:

A tubular end of a terminal in which a conductor is inserted prior to being soldered. It is also the hollow cylinder at the rear of a solder contact where a wire is inserted and soldered in place.

Solid Conductor:

A conductor consisting of a single wire.

Spring Finger Action:

Design of a contact as used in a printed circuit connector or a socket contact, permitting easy, stress-free spring action to provide contact pressure and/or retention.

Step Index Fiber (Fiber Optic):

A multimode fiber consisting of a core of uniform refractive index surrounded by cladding of a slightly lower refractive index. Accepts light rays over wider angle, but has smaller bandwidth than single mode fiber. See also Graded Index Fiber and Single Mode Fiber.

Stranded Conductor:

A conductor composed of groups of wires twisted together.

Surface Mounting:

The electrical connection of components to the surface of a conductive pattern without utilizing component holes in a circuit board.