Xmodem Definition

other

A public domain file transfer protocol used in asynchronous data communications, XMODEM organizes data into 128-byte blocks and employs a cyclic redundancy check (CRC) for error control. XMODEM was developed by Ward Christensen in 1977 and quickly became popular in the bulletin board system (BBS) community for file downloads. XMODEM has largely been replaced by ZMODEM. See also asynchronous, BBS, block, CRC, error control, Kermit, modem, YMODEM, and ZMODEM.

Webster's New World Telecom