Fluke DSP-4100 User Manual page 205

Glossary B
HDTDX
HDTDX 
High-definition time domain crosstalk. The HDTDX analyzer locates sources of NEXT
along cabling. This measurement technique is patented by Fluke Networks.
Horizontal Cabling
The cabling between a telecommunications outlet and a horizontal cross-connect.
Horizontal Cross-Connect
A group of connectors, such as a patch panel or punch-down block, that allows equipment
to be cross-connected with patch cords or jumpers. The horizontal cross-connect is usually
located in a wiring closet.
Impedance
Opposition to the flow of ac (alternating current) signals. Impedance is caused by
inductance and capacitance. Unlike resistance, impedance varies with the frequency of the
applied ac signal.
Impedance Discontinuity
An abrupt change in a cabling's characteristic impedance. Impedance discontinuities can
be caused by faulty connections, mismatched cable types, and untwisted sections on
twisted pair cable. Also called an anomaly.
Inductance
A property of a device that tends to oppose changes in current. Inductance is an
undesirable characteristic of cables because it causes signal attenuation.
Inductive Pickup
A device that emits sound when placed near a source of electromagnetic emissions.
Inductive pickups are used to locate individual cables in a bundle.
Jabber
A network fault condition where a frame longer than 1518 bytes is detected. Network
protocols specify a maximum packet length that one station may transmit before other
stations are allowed to transmit.
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