Until Gigabit Ethernet, LANs typically used how many pairs of the UTP cable?

Gigabit Ethernet is a significant advancement in networking technology that was introduced to support higher data rates. Prior to Gigabit Ethernet, typical Local Area Networks (LANs) predominantly utilized two pairs of Unshielded Twisted Pair (UTP) cable.

This approach involved using one pair for sending data and another pair for receiving data, allowing for simultaneous communication. This was sufficient for older Ethernet standards, such as 10BASE-T and 100BASE-TX, which operated at speeds of 10 Mbps and 100 Mbps, respectively. The two-pair configuration was efficient and economical for these networking speeds because the additional bandwidth could be effectively managed within that limited pair count.

In contrast, Gigabit Ethernet (1000BASE-T) requires all four pairs in a UTP cable to achieve its higher data transmission rates. Therefore, the context of the question centers around the technology that was prevalent before the advancements made by Gigabit Ethernet, solidifying the use of two pairs of UTP cables as the standard configuration for LANs prior to that point.