DIRECT CURRENT - A direct current is one which flows in one direction. Further classifications of direct currents are: a) Continuous currents which are steady, non pulsating direct currents: b) Constant currents, which continue to flow for a considerable time in the same direction and with unvarying intensity; and c) Pulsating currents, which are regularly varying continuous currents. Abbreviations DC and dc.
DIRECTION OF LAY - The lateral direction in which the strands of a cable run over the top of the cable as they recede from you looking along the axis of the cable.
DISPERSION - A general term for those phenomena that cause a broadening or spreading of light as it propagates through an optical fiber. The three types are modal, chromatic, and waveguide.
DOD - Abbreviation for the U. S. Department of Defense.
DOUBLE SHIELD - Two shields, one over the other. Maximum coverage is 98%.
DP - Abbreviation for data processing.
DRAIN WIRE - An uninsulated solid or stranded tinned copper wire which is placed directly under a shield. It touches the shield throughout the cable, and, therefore, may be used in terminating the shield to ground. A big labor saver in terminating all shielded cables. It is completely necessary on spiral shielded cables because it eliminates the possibility of induction in a spiral shield.
DRAWING - In wire manufacturing, pulling of metal through a die or series of dies to reduce diameter to a specific size.
DROP CABLE - In a CATV system, the transmission cable from the distribution cable to a dwelling.
DUCT - An underground or overhead tube for carrying electrical conductors.
DUPLEX - Two conductors twisted together, usually with no outer covering. This word has a double meaning and it is possible to have parallel wires and jacketed parallel wires and still refer to them as a duplex.
