Figure 2-34.—Twisted component or multiconductor cable.TWISTED COMPONENT OR MULTI-CONDUCTOR CABLES. —Twisted componentcables consist of multi-insulated wires (solid orstranded), with up to 120 conductors. They can besingle wires or twisted pairs. The cable is concentric inshape and the larger cables are usually semi-rigid toprovide support and put less strain on the cable itselfand its connector (fig. 2-34). Depending on the lengthof the cable, popular cable types for large main-frames and minis include 2U/2UW/LS2U or2AU/2WAU/LS2AU. The construction and adescription can be found in NEETS, Module 19, TheTechnician's Handbook. Twisted component cablescan be terminated with rectangular multipin connectorsor circular multipin connectors. They can be used forparallel and serial data transfer and in all types ofcomputers.COAXIAL CABLES. —Coaxial cables aredesigned to transmit signals efficiently between 1 kHzand 4000 MHZ with minimum loss and little or nodistortion. A coaxial cable is made of a central signalconductor covered with an insulating material (thedielectric core), which in turn, is covered by an outertubular conductor (the return path). The cable is calledcoaxial because the conductors, usually two or three,are separated by the dielectric core. The inner core canbe solid or stranded wire that is bare, timed, or silvercoated. Coaxial cables always have an outer shielding;refer to MIL-C-17 for specifications. Commonly usedcoaxial cables include RG-12A, RG-58, and RG-59 forcoaxial and TRF-8 and TRF-58 for triaxial. Coaxialcomponent cables are terminated with circular multipinconnectors. Coaxial cables are used for serial transferof data. Figure 2-35 shows examples of two types ofcoaxial cable: single and triaxial.FIBER OPTIC CABLES. —Refer to NEETS,Module 24, Introduction to Fiber Optics, for a detaileddiscuss of the fiber optic cabling. Fiber optic cables areused for serial transfer of data.CAUTIONCARE SHOULD ALWAYS BEEXERCISED WHEN HANDLINGCABLES. SEVERE BENDING ANDHANDLING OF THE CABLE BY ITSCONNECTOR CAN CAUSE DAMAGE.Figure 2-35.—Coaxia1 cable: A. Single; B. Triaxial.2-25
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