# Full duplex

Full duplex means simultaneous bidirectional communications.
Both sides send and receive with virtually no turnaround time.

On ASCII terminals used with the D3 System, full duplex
is the mode in which characters entered from a keyboard are transmitted
to the D3 host but not displayed to the screen. Normally, D3 ports
are configured for full duplex also called echo-plex. Every character
received is echoed to the terminal. Upon a keystroke, the character
viewed on the screen has made a round trip from the system and back
to the screen.

## See also

- [echo command](https://d3codex.com/tcl/echo-command/)
- [echo statement](https://d3codex.com/pickbasic-flashbasic/echo-statement/)
- [Half duplex](https://d3codex.com/definitions/half-duplex/)

---
Source: https://d3codex.com/definitions/full-duplex/ - part of the D3Codex reference.