Category 4 Cabling (Cat 4)

Cat 4 or Category 4 Cabling is the fourth-lowest grade of unshielded twisted-pair (UTP) cabling. Category 4 cabling was designed to support digital voice and data communication at speeds up to 16 Mbps.

Category 4 Cabling
Category 4 Cabling

It uses 22-gauge or 24-gauge copper wires in a configuration of four twisted-pairs enclosed in a protective insulating sheath. Category 4 cabling can support standard 10BaseT types of Ethernet networks. It was also commonly used in older 16-Mbps Token Ring installations.

Category 4 cabling still has an installed base in older buildings where it is often cheaper to use the existing cabling than to upgrade to newer grades. Installing higher-grade cabling for backbone cabling in vertical rises and elevator shafts can extend the life of work areas that still use category 4 cabling. However, if greater speeds are required at users’ workstations, the best solution is to rewire the work areas using category 6 cabling.

Category 4 Cabling Characteristics

The following table summarizes the electrical characteristics of category 4 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 20 MHz
Attenuation20 decibels/1000 feet31 decibels/1000 feet
NEXT41 decibels/1000 feet36 decibels/1000 feet
Resistance28.6 ohms/1000 feet28.6 ohms/1000 feet
Impedance100 ohms (± 15%)100 ohms (± 15%)
Capacitance18 pF/feet18 pF/feet

Source: ANSI-TIA-EIA 568-B – Commercial Building Telecommunications Cabling Standard


Articles posted after being checked by editors.

Recent Content

link to Named Pipe

Named Pipe

Named Pipe is an interprocess communication mechanism that provides reliable, connection-oriented, two-way communication between processes on two computers. Named pipes are one form of client/server...