Common Types of Cables:Shielded Twisted Pair- Similar to UTP, Pairs Shielded, Core Shielded. Screened Twisted Pair – Hybrid of STP and UTP, Foil shielded or screen.( Bothe the cables must be grounded end to end with no gaps in shield coverage. Unshielded Twisted Pair - 4 pairs of copper cable, number of twists vary per inch, no shielding, very easy to work with, Common for LAN, cat 3,5,5e,6 and 7, most susceptible to EMI. COAXIAL – Single conducting core, core shield, mesh shield. 50 OHM RG-58(thinnet) is for outdated 10Base-2 Ethernet, 75OHM RG-6u commonly used for HDTV and broadband applications. FIBER - Central Glass Core, cladding prevents light loss, Dialectric strengthening material protects core, Single strand, dual strand and multistrand cables are commom.

Common types of measurements. Decibles – Attenuation – Loss of signal.Chromatic Dispersion- The spreading of a particular light pulse because of the varying refraction rates of the different colored wave-lengths. Different wavelengths travel along an optical medium at different speeds. Wavelengths reach the end of the medium at different times, causing the light pulse to spread. This chromatic dispersion is expressed in picoseconds per kilometer per nanometer ( of band-width). It is the sum of material and waveguide dispersions. Propagation Delay – The difference in time between when a signal is trans-mitted and when it is received.Delay Skew - The difference in propagation delay between the fastest and slowest pair in a cable or cabling system. See Chapter 1 for more information on delay skew.

Organizations- ANSI, America Nations Standards Institute –1918, 5 engineering societies, 3 government agencies, over 1400 private companies, It encourages voluntary compliances, with adopted standards and methods. EIA, Electronic Industries Alliance, 1924, manufactures consortium, electronics sectors: components, consumer electronics, electronic information, industrial electronics,