CAT5, CAT5e, CAT6, CAT7 and CAT7a Information


Xmultiple's Engineering Department

Listed below are frequently asked question regarding CAT5, CAT5e, CAT6, CAT7 and CAT7a

To help our customers understand CAT5 and CAT5e specifications this document is a comparison between Category 5, Category 5E, Category 6 and Category . Xmultiple connectors are manufactured to work with CAT5 and CAT5e and the emerging CAT6.

This Comparison between CAT5, CAT5e, CAT6, CAT7 is In the context of the 100-ohm UTP (Unshielded Twisted Pair) type of cable used for Ethernet wiring. CATx is an abbreviation for the category number that defines the performance of building telecommunications cabling as outlined by the Electronic Industries Association (EIA) standards.

UTP cabling has become the cable structure of most companies because it was easier to install and less expensive. UTP CAT3 and CAT4 were used for a quite limited time since the emergence of 100Base-TX networks resulted in a quick change over to CAT5. The current increase of use of gigabit (1000Base-TX) Ethernet LANs created a need for another specification which is CAT6. CAT5e. CAT5e is now being superseded by CAT6 cable and there is a developing standard for CAT7. Xmultiple connectors are designed to work with the emerging CAT6 with most of our product line series. Listed below are specifications of the different CATx categories in use today.

Specifications for Cat3, Cat4, Cat5, Cat5e, Cat6, and Cat7

Category Type Spectral R/W Length Lan Applications Notes
CAT3 UTP 16MHz 100m 10Base-T, 4Mbps For telephone
CAT4 UTP 20MHz 100m 16Mbps Rare
CAT5 UTP 100MHz 100m 100Base-T, ATM, CDDI LAN Use
CAT5e UTP 100MHz 100m 100Base-T LAN Use
CAT6 UTP 250MHz 100m   Emerging
CAT7 ScTP 600MHz 100m    

CAT5 and CAT5e are almost the same. The CAT5e specification includes some additional limits over the CAT5 specification. The reality therefore is the CAT5 is in fact CAT5e. It just not certified as such. Below is a comparison of the extra specifications.


CAT5, CAT5e, and CAT6 UTP (Solid Cable) Specifications Comparison
  Category 5 Category 5e Category 6
Frequency 100 MHz 100 MHz 250 MHz
Return Loss (Min. at 100MHz) 16.0 dB 20.1 dB 20.1 dB
Characteristic Impedance 100 ohms กำ 15% 100 ohms กำ 15% 100 ohms กำ 15%
Attenuation (Min. at 100 MHz) 22 dB 22 dB 19.8 dB
Next (Min. at 100MHz) 32.3 dB 35.3 dB 44.3 dB
PS-Next (Min. at 100MHz) no specification 32.3 dB 42.3 dB
ELFEXT (Min. at 100 MHz) no specification 23.8 dB 27.8 dB
PS-ELFEXT (Min. at 100 MHz) no specification 20.8 dB 24.8 dB
Delay Skew (Max. per 100 m) no specification 45 ns 45 ns


CAT6 & CAT6a Strict Specifications With More Stringent Crosstalk and System Noise Features.

Category 6 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 / 1000BASE-TX (Gigabit Ethernet).

The cable contains four twisted copper wire pairs. This is the same as CAT5 and CAT5e copper cable standards. Cat-6 is also made with 23 gauge wire, however this is not a requirement. The ANSI/TIA-568-B.2-1 specification indicates the cable may be made with 22 to 24 AWG wire. For local area network patch cables, Cat-6 is normally terminated with 8P8C modular connectors. The modular connectors are the RJ-45" electrical connectors manufactured by Xmultiple and other connector companies. Cat-6 RJ45 connectors are made to higher standards with improved gold plating and higher performance design of contact pins alignment which reduce noise caused by crosstalk and system interference. Attenuation, NEXT (Near End Crosstalk), and PSNEXT (Power Sum NEXT) are all significantly lower when compared to Cat-5/5e. There is one problem with Cat-6 cables which is they are larger and increase size. Therefore they are more difficult to attach to 8P8C connectors without a special modular piece. They are technically not standard compliant if they do not insert into a RJ45 connector. The maximum allowed length of a Cat-6 cable is 100 meters (330 ft) when used for 10/100/1000baseT and 55 meters (180 ft) when used for 10GbaseT.

CAT7 Strict Specifications For Crosstalk

Category 7 cable (Cat7), (ISO/IEC 11801:2002 category 7/class F), is a cable standard for Ethernet and other interconnect technologies. CAT 7 is backwards compatible with traditional Cat5 and Cat6 Ethernet. Cat7 features even more strict specifications for crosstalk and system noise than Cat6. Shielding has been added for individual wire pairs on the Category 7 cable.

Cat7 has been designed as a standard for Gigabit Ethernet over 100m of copper cabling The cable contains four twisted copper wire pairs, just like the earlier standards. Cat7 can be terminated either with 8P8C compatible GG45 electrical connectors which incorporate the 8P8C standard or with TERA connectors. When combined with GG45 or TERA connectors, Cat7 cable is rated for transmission frequencies of up to 600 MHz. Xmultiple's UltraJAX connectors are designed specifically for these high speeds with not contact pins and a printed circuit board with contact pads integrated into the RJ45 style housing.

CAT7a For Frequencies up to 1000MHz

Category 7a which is also commonly referred to as Augmented Category 7, operates at frequencies up to 1000 MHz. CAT7a is designed for multiple applications in a single cable including 40 Gigabit Ethernet, 100 Gigabit Ethernet, and CATV (862 MHz).[1][2][3). Test results have shown 40 Gigabit Ethernet will work up to 50 meters and 100 Gigabit Ethernet is possible up to 15 meters. Small form factor pluggable products are available by Xmultiple in both copper and fiber optics for the 40GB and 100 GB applications.

Retrun Loss Analysis for RJ Connectors


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