A terminal emulation is a software program that allows personal computers(PCs) to emulate the behavior of terminals or other computers.
After emulation, the personal computer appears to other computers as a terminal with which the same services and functions can be executed as with the actual terminal. This includes access to hosts or multi- user systems. The terminal emulation defines the method by which characters to be displayed on the screen are encoded.
The usual terminal emulation method for personal computers is based on an ANSI emulation, Unix systems usually use a VT100 or VT102 emulation. The best known terminals that have been emulated are DEC's VT100, VT220 and IBM's Terminal 3270. One of the simplest and oldest emulations is the TTY emulation (Teletype), which was developed for the teleprinter.