The 3B2T coding is a simple ternaryline coding in which a group of three bits (3B) are mapped with two ternary signal levels (ternary block 3T).
This means that a total of 8 binary values are mapped to 9 signal values.A total of nine states can be represented by this mapping. The 3B2T coding is used, among other things, on the physical layer of Reduced Twisted Pair Gigabit Ethernet (RTPGE).
The coding method does not guarantee freedom from direct current. This and the clock recovery must be ensured with additional measures, such as scrambling.