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Category 6 or Cat 6
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Cat6 cable commonly referred to as Cat 6, is a cable standard for
Gigabit Ethernet and other network protocols that is backward compatible with
the Category 5/5e and Category 3 cable standards. Cat-6 features more stringent
specifications for crosstalk and system noise. The cable standard provides
performance of up to 250 MHz and is suitable for 10BASE-T / 100BASE-TX and
1000BASE-T (Gigabit Ethernet). It is expected to suit the 10GBASE-T (10Gigabit
Ethernet) standard, although with limitations on length if unshielded Cat 6
cable is used. The cable contains four twisted copper wire pairs, just like
earlier copper cable standards. Although Cat-6 is sometimes made with 23 gauge
wire, this is not a requirement; the ANSI/TIA-568-B.2-1 specification states the
cable may be made with 22 to 24 AWG gauge wire, so long as the cable meets the
specified testing standards. When used as a patch cable, Cat-6 is normally
terminated in 8P8C modular connectors, often incorrectly referred to as "RJ-45"
electrical connectors. Cat-6 connectors are made to higher standards that help
reduce noise caused by crosstalk and system noise. Attenuation, NEXT (Near End
Crosstalk), and PSNEXT (Power Sum NEXT) are all significantly lower when
compared to Cat-5/5e. Some Cat-6 cables are too large and may be difficult to
attach to 8P8C connectors without a special modular piece and are technically
not standard compliant. If components of the various cable standards are
intermixed, the performance of the signal path will be limited to that of the
lowest category. As with all cables defined by ANSI/TIA/EIA-568-B, the maximum
allowed length of a Cat-6 horizontal cable is 100 meters (330 ft) in length,
depending upon the ratio of cord length:horizontal cable length. The cable is
terminated in either the T568A scheme or the T568B scheme. It doesn't make any
difference which is used, as they are both straight through (pin 1 to 1, pin 2
to 2, etc). Mixing T568A-terminated patch cords with T568B-terminated horizontal
cables (or the reverse) does not produce pinout problems in a facility. Although
it may very slightly degrade signal quality, this effect is marginal and
certainly no greater than that produced by mixing cable brands in-channel. The
T568B Scheme is by far the most widely used method of terminating patch cables.
Crossover is used for hub to hub, computer to computer, wherever two-way
communication is necessary. All gigabit ethernet equipment, and most new
10/100Mb equipment, supports automatic crossover, meaning that either a
straight-through or crossover cable may be used for any connection. However,
older equipment requires the use of a straight-through cable to connect a switch
to a client device, and a crossover cable to connect a switch to a switch or a
client to a client. Crossover cables can be constructed by wiring one end to the
T568A scheme and the other end with the T568B scheme. This will ensure that the
Transmit (TX) pins on both ends are wired through to the Receive (RX) pins on
the other end. |
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