Xmodem Last modified: Thursday, November 08, 2001
Originally developed in 1977 by Ward Christensen, Xmodem is one of the most popular file-transfer protocols. Although Xmodem is a relatively simple protocol, it is fairly effective at detecting errors. It works by sending blocks of data together with a checksum and then waiting for acknowledgment of the block's receipt. The waiting slows down the rate of data transmission considerably, but it ensures accurate transmission. Xmodem can be implemented either in software or in hardware. Many modems, and almost all communications software packages, support Xmodem. However, it is useful only at relatively slow data transmission speeds (less than 4,800 bps). Enhanced versions of Xmodem that work at higher transmission speeds are known as Ymodem and Zmodem.
•E-mail this definition to a colleague• For internet.com pages about Xmodem . Also check out the following links! XMODEM, YMODEM, and ZMODEM  Uploading and downloading files from you home computer over a modem. Xmodem, Ymodem, and Zmodem differences Offers a brief technical explanation of the differences between Xmodem, Ymodem, and Zmodem, with tips on how they're normally used.	Communications Standards File Transfer checksum communications protocol communications software Kermit modem protocol Ymodem Zmodem Give Us Your Feedback Modems modem Products Shop here to Save Money on Modems at DealTime! Search by brand or type to find the best price across 100s of stores! Shop by Top Models: U.S. Robotics USR5686D Analog Modem 16 store offers from $55 - $112 Hiro (H50113) Analog Modem 4 store offers from $20 - $25 D-link DSL-2320B 8 store offers from $47 - $60 D-link (DCM-202) Cable Modem 16 store offers from $50 - $80 Efficient Networks SpeedStream 4060 DSL Modem (161-4060-101) 1 store offers from $69 - $69