Category 5 cabling

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Category 5 cabling is a level 5 grade of unshielded twisted-pair (UTP) cabling.

What is Category 5 cabling?

Category 5 cabling was designed to support digital voice and data communication at speeds up to 100 Mbps. It uses 22-gauge or 24-gauge copper wires in a configuration of four twisted-pairs enclosed in a protective insulating sheath. Before Category 6 was released, Cat5E Cable was the most used type of cabling on computer networks.

CAT5 cabling is the standard grade of UTP cabling for networks such as:

  • The standard 10BaseT variety of Ethernet
  • Fast Ethernet networks of the 100BaseTX variety
Category 5 Cable
Category 5 Cable

Category 5 cabling is always recommended for new installations of premise cabling and for upgrading existing premise wiring for higher-speed networks, because of its superior electrical characteristics. It is the highest grade of UTP cabling currently recognized by the Electronic Industries Alliance (EIA) and Telecommunications Industry Association (TIA), although proposals there have been made for higher category 6 and category 7 grades.

See: difference between CAT5 and CAT6 cabling.

Many vendors offer an enhanced category 5 cabling grade with electrical characteristics exceeding those of standard CAT5. Enhanced CAT5 cabling supports data transmission up to frequencies of 350 MHz, and new standards are under development to allow even higher data transmission frequencies.

Category 5 Cabling Characteristics

The following table summarizes the electrical characteristics of CAT5 cabling at different frequencies, which correspond to different data transmission speeds. Note that attenuation increases with frequency, while near-end crosstalk (NEXT) decreases.

CharacteristicValue at 10 MHzValue at 100 MHz
Attenuation20 decibels/1000 feet67 decibels/1000 feet
NEXT47 decibels/1000 feet32 decibels/1000 feet
Resistance28.6 ohms/1000 feet28.6 ohms/1000 feet
Impedance100 ohms (± 15%)100 ohms (± 15%)
Capacitance18 pF/ft.18 pF/ft.


Category 5 cabling is usually referred to simply as “CAT5.” UTP cables using CAT5 should be no more than 90 meters in length for typical Ethernet and Fast Ethernet installations, and patch cords should be no longer than 10 meters.