Kermit is a terminal emulator and file transfer program delevoped by Columbia University. It's popularity springs from the large range of computers that Kermit could be used to access, from IBM mainframes to MS-DOS PCs.
A Kermit variant named G-Kermit was released under the GNU Public License. This is available in most Linux distributions.
The recent Kermit and Zmodem protocols are built upon the same technologies. Zmodem has better performance in calls with high error rates. Kermit has been ported to more host platforms.