Several international modem standards set by the Consultative Committee for International Telephony and Telegraphy. The standards help buyers make sure modems they buy will communicate with other modems. The standards, formerly used primarily outside the United States, have been accepted almost universally since the advent of the 2400 bits per second (bps) modems. Not all are relevant to computer users. Examples include: V.21, V.22, V.22bis, V.23, V.26, V.26bis, V.27, V.27bis, V.27ter, V.29, V.32, V.32bis, V.34, V.42, V.42bis.