As far as I know, 10BASE-T and 100BASE-T (types of UTP) use two pairs of wires, while 1000BASE-T has four pairs of wires. But when I look up the photo of 10BASE-T on google, it indeed contains four wire pairs which are four different colours like this below.


Is it just that it has four pairs of wires but only two of them are used to connect nodes? or Is the photo I found wrong?

A website that confused me. https://www.carleton.edu/sysnet_docs/wiring_docs/10baseTprocs.html#:~:text=Currently%2C%20most%20campus%20computers%20with,cabling%20will%20contain%204%20pairs.

Note that I am not criticizing this website.

I am quite new to network technology. Sorry if this question seems fool.

  • Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
    – Ron Maupin
    Commented Dec 23, 2021 at 19:48

1 Answer 1


You are correct that 10Base-T and 100Base-Tx use two pairs for communication, while 1000Base-T uses all four.

You may be confused because you're conflating different standards for different items.

10Base-T, 100Base-Tx, etc., are signaling and electrical standards from IEEE (802.3i).

The cable itself is defined by ISO/IEC 11801, and is called Category 5, 5e, 6, etc.

The connectors commonly used on the cables are defined by ANSI, and are called TIA-568A or TIA-568B, depending on the pairing.

  • 1
    Might be noteworthy that 10BASE-T (and the previous StarLAN aka 1BASE5) were designed to use the pre-existing and already common twisted-pair installations.
    – Zac67
    Commented Jun 2, 2021 at 13:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.