noun Technical meaning of v.42bis (communications, standard) An extension of the ITU-T V.42 standard modem protocol to included compression using a Lempel-Ziv related technique, which detects frequently occurring character strings and replaces them with tokens. This is similar to the Unix compress utility. Typical compression for text is 50% or better; with nearly 20% gain from synchronous conversion this gives reduces transmission time by almost 60%. 1
