Operation Manual

DSP-4000 Series
Users Manual
B-8
Level I, Level II, Level IIE, and Level III Accuracy
Levels of performance requirements for field testing of installed, unshielded twisted pair
cable links. Level I is acceptable for testing channels. Level II has tighter limits and is
preferred for testing basic links. These requirements, which evolve over time, are
published in TSB-67. Levels IIE and III apply to Cat 5E and the proposed Cat 6 standards,
respectively.
Link Pulse
A single-bit, 100 ns test pulse that is transmitted at least every 50 ms during idle periods on
10BASE-T link segments to verify link integrity.
MUTO
Multi-user telecommunications outlet. A multiport outlet installed in the work area to
support a group of users. The MUTO cabling standard addresses the need for longer
sections of cable that allow more flexibility when wiring modular offices.
Near-End Crosstalk (NEXT)
The amount of coupling loss (in decibels) occurring when a signal generated at the near
end of one cable pair is received as crosstalk at the near end of another cable pair. Higher
NEXT levels correspond to better cabling performance.
NVP
Nominal Velocity of Propagation. The speed of a signal through a cable, expressed as a
percentage of the speed of light. Typically, the speed of a signal through a cable is between
60% and 80% of the speed of light.
Packet
A group of bits in a specific format, containing a data message that is sent over a network.
Permanent Link
A network connection consisting of (1) one connection at the patch panel, (2) a horizontal
cable segment up to 90m (295 ft), (3) an optional consolidation point, and (4) one
connection at a telecommunications outlet. Permanent link test connections are similar to
basic link connections, except that the effects of the test equipment patch cables are
excluded from the test results.