2B1Q (2 Binary, 1 Quaternary) is a line coding technique used in digital communications where 2 binary bits are encoded as 1 quaternary symbol. This is used in HDSL and IDSL technologies.
| Binary Input (2 bits) | Quaternary Output (Voltage Level) | Symbol |
|---|---|---|
| 00 | -3V | Q0 |
| 01 | -1V | Q1 |
| 10 | +1V | Q2 |
| 11 | +3V | Q3 |