An asynchronous communications protocol designed by Chuck Forsberg that extends Xmodem by increasing the transfer block size and by supporting batch file transfers. This enables you to specify a list of files and send them all at one time. With Xmodem, you can send only one file at a time.
Meaning of YMODEM in English
DAX English glossary of key connectivity terms. Английский глоссарий основных терминов по коммуникациям DAX. 2012