1. An synchronous file transfer protocol for personal computers that makes the error-free transmission of computer files with a modem easier. ZMODEM is a very fast protocol that lets you use wild-card file names for transfers. lt's also well-liked because you can resume the transfer of a file if the first attempt is interrupted before completion. Next to XMODEM, ZMODEM is the most popular transfer protocol and is included in most communications applications.

2. A file transfer protocol that is similar to Xmodem and Ymodem. It is better at handling large data transfers and includes a restart feature which allows a download to be resumed.