Enterprise Design Guide - Public - CommScope

Twisted Pair Cable Performance
Category 6A, Category 6 and Category 5e cables are capable of supporting full duplex
parallel transmission required by gigabit Ethernet and can deliver fast transmission protocols
such as broadband video.
A horizontal twisted pair link should deliver a minimum of 10 dB of PSACR at 100 MHz.
While some equipment can accept signal as low as 3 dB, 10 dB is a good rule of thumb.
However, an experienced designer knows that factors like transmission echo and impedance
mismatch can cause crippling power loss and the breakdown of the channel. Using a cable
with higher bandwidth, especially in links approaching the 90 meter limit, will keep high speed
networks performing as required. Many network problems are eliminated by installing cables
with the extra ‘headroom’ provided by higher bandwidth.
PSACR for U/UTP channels
70 dB
60 dB
50 dB
40 dB
30 dB
20 dB
10 dB
0 dB
-10 dB
-20 dB
-30 dB
1
CommScope’s enhanced cables
offer 6 - 8 dB more headroom at
critical operating frequencies
31.25 62.5 100 200 250 300 400 500 MHz
Cat6a
500 MHz
Cat6e
550 MHz
Cat6
400 MHz
Typical vs. tested
Some cables have their performance listed in ‘typical’ performance values. However, sweeptesting
is necessary to confirm actual performance. CommScope strongly recommends
specifying cable that has been sweep-tested to the listed frequency with test confirmation
available for inspection.
Cat6 standard
250 MHz
Cat5e C/S
350 MHz
Cat5e C/S
200 MHz
Cat5e standard
200 MHz
Because twisted pair cables are usually used in the horizontal segment of the network, they are
usually plenum or riser listed. See Safety Listing/page 35 for details.
Insist on twisted pair cable
that has been sweep-tested
to verify performance
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