The international standard, controls transmission at 300bps.

A CCITT 300 Bps dial modem recommendation; similar to Bell 103.

A CCITT Recommendation for modem communications over standard commercially available lines at 300 b/s. This protocol is generally not used in the United States.

An ITU-T modem protocol for 300 bits per second two-wire full-duplex communications using Frequency Shift Keying modulation. All modern modems support both V.21 and the close variant, Bell 103.

300 bps, full duplex for dial up lines.

CCITT standard for modem communications at 300bps. Modems made in the US follow the Bell 103 standard.

300bit/s duplex modem for use over PSTN.

An ITU-T standard for modems operating in asynchronous mode at speeds up to 300 bps, full-duplex, on public-switched telephone networks.

An ITU-T standard that describes 300bps modems for use in the PSTN.