Screened and Shielded Cabling: Definitions and Acronyms
absorption loss: Signal loss in a metallic media due to impedance losses and heating of the material
alien crosstalk: Undesired differential mode signal coupling between balanced twisted-pair cables
balance: The relationship between the differential signal and common mode signals on a twisted-pair
common mode: Signals that are in phase and are measured referenced to ground
differential mode: Signals that are 180° out of phase and measured referenced to each other
electromagnetic compatibility: The ability of a system to reject interference from noise sources (immunity) and operate without interfering with other devices or equipment (emissions)
equal level transverse conversion transfer loss: The ratio of the measured common mode voltage on a pair relative to a differential mode voltage applied on another pair and normalized to be independent of length
fully-shielded: A construction, applicable to category 7 and 7A cabling, where each twisted-pair is enclosed within an individual foil screen and the screened twisted-pairs are enclosed within an overall braid or foil
ground loop: A difference in voltage potential between two ground termination points that results in an induced common mode noise current
modal conversion: Undesired conversion of differential mode signal to common mode signal and vice versa that results from poor balance
screen: A metallic covering consisting of a longitudinally applied aluminum foil tape
screened: A construction, applicable to category 6A and lower-rated cabling, where an assembly of twisted-pairs is enclosed within an overall metal foil.
Shannon capacity model: A calculation to compute the maximum theoretical amount of error-free digital data that can be transmitted over an analog communications channel within a specified transmitter bandwidth and power spectrum and in the presence of known noise (Gaussian) interference
shield: A metallic covering consisting of an aluminum braid
shielded: See fully-shielded
transfer impedance: A measure of shield effectiveness
transverse conversion loss: The ratio of the measured common mode voltage on a pair relative to a differential mode voltage applied on the same pair
transverse conversion transfer loss: The ratio of the measured common mode voltage on a pair relative to a differential mode voltage applied on another pair
Acronyms
BER: Bit error rate
DSP: Digital signal processing
ELTCL: Equal level transverse conversion transfer loss
EMC: Electromagnetic compatibility
F/UTP: Foil unshielded twisted-pair (applicable to category 6A and lower-rated cabling)
IEEE: Institute of Electrical and Electronics Engineers
LAN: Local area network
NIC: Network interface card
S/FTP: Shielded foil twisted-pair (applicable to category 7 and 7A cabling)
SNR: Signal-to-noise margin
TCL: Transverse conversion loss
TGB: Telecommunications grounding busbar
TGMB: Telecommunications main grounding busbar
UTP: Unshielded twisted-pair (applicable to category 6A and lower-rated cabling)
Vrms: Volts, root mean square
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