zero-dispersion wavelength - Wavelength at which the chromatic dispersion of an optical fiber is zero. Occurs when waveguide dispersion cancels out material dispersion.

Z-gap - Spacing in fusion splicing.

zip-cord - In optical communications, a twofiber cable consisting essentially of two single-fiber cables having their jackets conjoined by a strip of jacket material.

zone - A specific area of protection, or a portion of a large protected area. In wireless networking, a zone consists of one access point (AP) and the group of devices associated with that AP. Also called a cell.

zone box - An enclosure used to house one or more of the following: a consolidation point, a horizontal connection point, building automation system outlets.

zone cabling - See open office cabling.

zone of protection - The area in close proximity to and within a building's lightning protection system. Several factors may make this area relatively immune to direct lightning strikes.