Definitions for "V.21"
Keywords:  bps, ccitt, duplex, pstn, itu
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.
defines modulation used for transmission of control messages in conventional fax
Keywords:  communication