CHASSIS WIRING receiving (or both) electrical or electromagnetic signals, usually in distinction from other parallel paths. (4) Used in conjunction with a predetermined letter, number, or codeword to reference a specific radio frequency. (5) A path along which signals can be sent; e.g., data channel, output channel. (6) The portion of a storage medium that is accessible to a given reading or writing station; e.g., track, band. (7) In information theory, that part of a communications sys- tem that connects the message source with the message sink. CHARACTER Letter, digit, or other special form that is used as part of the organization, control, or representation of data. A char- acter is often in the form of a spatial arrangement of adjacent or connected strokes. CHARACTER CODE A correspondence between a character set and a set of integers. CHARACTERISTIC, CRITICAL A critical characteristic is one that analysis indicates is likely, if defective, to create or increase a hazard to human safety or to result in failure of a weapon system or major system to perform a required mission. CHARACTERISTIC IMPEDANCE The ratio of voltage to cur- rent in a propagating wave, i.e., the impedance offered to this wave at any point of the line. (In printed wiring, its value depends on the width of the conductor, the distance from the conductor to ground planes, and the dielectric constant of the media between them.) CHARACTERISTIC, MAJOR A major characteristic is one that analysis indicates is not critical but is likely, if defective, to result in failure of an end item to perform a required mission. CHARACTERISTIC, MINOR A minor characteristic is one that analysis indicates is significant to product quality but is not likely, if defective, to impair the mission performance of the item. CHARACTER SET A set of graphic symbols independent of font. A character set does not include specification of codes to represent characters. CHARACTERS PER INCH (CPI) The number of bar coded characters that are displayed in each inch of bar code. CHASSIS The metal structure that supports the electrical compo- nents that make up the unit or system. CHASSIS WIRING Chassis wiring may consist of hookup wire, lead wire, shielded cable, jacketed multiconductor cable, coaxial cable, or twisted multiconductor groups of wires or cables, or wires 53