Kermit is noted for its transmission accuracy and slow transmission speeds due to its default settings that optimize for accuracy. However, Kermit can also be tuned to transfer data as quickly as any other data transfer protocol.
Kermit is not in the public domain, but Columbia University allows people to use the protocol for free, so almost all communications products support it. However, not all implementations support the full protocol. This has led some people to refer to an advanced version of Kermit as Super Kermit. Actually, there is only one version of the Kermit protocol, which supports all the advanced features usually attributed to Super Kermit, such as sliding windows and long packets.
Other file-transfer protocols used by modems include Xmodem and Zmodem.