10BASE-T is an Ethernet standard for local area networks (LAN) that requires only one copper twisted pair cable of Category 3 (CAT-3) or higher, either unshielded twisted pair (UTP) or shielded twisted pair (STP), for a maximum network segment length of 100 meters for UTP, or 200 meters for STP.

Its designation provides a quick summary of the characteristics of its physical medium: "10" denotes its maximum data transmission rate of 10Mbps; "BASE" is shorthand for "baseband transmission," meaning the medium exclusively transmits Ethernet signals; and "T" is a reference to the twisted pair cable needed for this standard.

The network topology used for a 10BASE-T network is the star configuration. In this type of topology, 12 or more computers are connected to a central hub or concentrator, essentially forming a star. The maximum number of devices or nodes connected to a single 10BASE-T network is 1024.

The twisted pair cable used for 10BASE-T is terminated at both ends with an RJ-45 connector. The connector has eight pins, but 10BASE-T requires only four pins, which are connected to two twisted pairs of wire. Pins 1 and 2 are used for transmission (positive and negative signals, respectively), and pins 3 and 6 are used for reception (positive and negative signals, respectively). The wires may be arranged in either a "straight through" or "crossover" fashion.

Each wire has a specific color for its insulation for easier configuration. The colors vary, depending on the type of wiring. For TIA/EIA-568-A T568A wiring, pin 1 is white/green, pin 2 is green, pin 3 is white/orange, and pin 4 is orange. For TIA/EIA-568-B T568B wiring, pin 1 is white/orange, pin 2 is orange, pin 3 is white/green, and pin 6 is green.

10BASE-T allows for a variety of types of wiring. However, there are certain parameters for the cable which must be met, and cable testers may be used to check the compatibility of a cable with a 10BASE-T network. Some of the characteristics noted are nominal impedance, propagation delay, attenuation, timing jitter, and various types of noise. Autonegotiation or NWay, the procedure of selecting common transmission parameters for two connected devices, is also a requirement for this standard.

In comparison to other 10Mbps Ethernet standards, 10BASE-T employs a thinner, more flexible cable than either 10BASE-2 or 10BASE-5, and it is relatively cheaper. Installation is also very easy, and some users may create their own 10BASE-T wires at home.