Recommendation V.22bis (11/1988): 2400 bits per second duplex modem using the frequency division technique standardized for use on the general switched telephone network and on point-to-point 2-wire leased telephone-type circuits
recommendation/international standard from the International Telecommunication Union
ITU Telecommunication Standardization Sector
2400 bits per second duplex modem using the frequency division technique standardized for use on the general switched telephone network and on point-to-point 2-wire leased telephone-type circuits