A program, similar to telnet, used to connect to remote
IBM mainframe hosts, many of which do not understand
telnet. The program emulates a 3270-type terminal.
For many tn3270 versions, the "clear screen" function is
activated by typing Control-Z. When logged on to an IBM host
and "HOLDING" or "MORE..." appears at the lower right corner
of the screen, the "clear screen" function must be entered to
display the next screen. tn3270 emulations usually include
function key definitions.
