V series
A set of standards published by the CCITT for "Data Communication over the Telephone Network". The following standards describe the important modulation techniques: V.17, V.21, V.22, V.22 bis, V.23, V.27 ter, V.29, V.32, V.32 bis. Other V standards include V.24, V.25 bis, V.42, V.42 bis.