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| H |
Half Duplex Transmission - Data transmission over a circuit
capable of transmitting in either direction, but not simultaneously.
HC - see Horizontal Cross Connect.
Headend - The equipment in a cable system which receives
the various program source signals,processes them, and retransmits
them to subscribers.
Headroom - The amount by which a cable exceeds NEXT.
Hertz - The unit of frequency, one cycle per second (abbreviated
Hz).
HF - High Frequency
Home Run - A cable run that connects a user outlet directly
with the telecommunications or wiring closet, with no intermediate
splices, bridges, taps, or other connections.
Horizontal Cabling, Horizontal Wiring - The portion of
the cabling system that extends from the work area outlet to
the horizontal cross connect in the telecommunications or wiring
closet.
Horizontal Cross Connect - A cross connect of horizontal
cabling to other cabling, e.g. horizontal, backbone, or equipment.
Host - Computer that offers services on a network.
Hub - A hardware device that contains multiple independent
but connected modules of network and internetworking equipment.
Hubs can be active (where they repeat signals set to them) or
passive (where they do not repeat but merely split signals sent
through them). Hub may also refer to a repeater, bridge, switch,
router, or any combination of these.
HVAC - Heating, ventilation, and air conditioning system.
Hybrid Cable - An assembly of two or more cables (of
the same or different types or categories) covered by one overall
sheath.
Hypalon - A DuPont trade name for a synthetic rubber
(chlorosulfonated polyethylene) used as insulating and jacketing
material for cabling. |
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