Which standard uses only 2 pairs of wires for communication?

The standard that utilizes only 2 pairs of wires for communication is 10BASE-T. This Ethernet standard is designed for use with twisted pair cabling, specifically Category 3 or higher. It operates at a data rate of 10 Mbps and employs a signaling method that requires only two pairs of wires: one pair for transmitting data and the other for receiving data.

This wire-pair configuration is advantageous for basic networking applications, especially in scenarios where cabling infrastructure may be limited or where cost-effective solutions are preferred. The use of only 2 pairs simplifies the installation process and reduces costs associated with cabling compared to standards that require more pairs.

In contrast, standards like 100BASE-TX utilize 2 pairs as well but are specifically optimized for 100 Mbps speeds, while 100BASE-FX employs a fiber optic medium and requires different configurations altogether. Similarly, 10BASE-FL, which also uses fiber optics, does not apply to twisted pair copper cabling standards.