TIA-232-F

TIA-232-F is a Telecommunications Industry Association standard for serial communication transmission of data previously referred to as “RS‑232”. It formally defines the signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment or data communication equipment), such as a modem.

NENA-STA-027, E9-1-1 PSAP Equipment Standards