It can use its own special fonts to fully emulate the special symbols displayed on a 3278 or 3279, or any constant-width X font.
x3270 is a full-featured X client. It participates in common X protocols, such as cut-and-paste and the WM_DELETE_WINDOW and WM_SAVE_YOURSELF messages. It is highly configurable and supports a wide range of keyboards. A pop-up keypad is available for selecting common 3270 function keys.
x3270 emulates one of four models of an IBM 3278 or 3279 terminal. The difference between the various models is the screen size. The emulation is not quite complete; x3270 understands extended field orders but does not implement some of the extended attributes (outlining, extended validation, etc.). x3270 supports color displays in one of two ways: in 3278 mode by displaying text with different attributes in different colors, or in 3279 mode by implementing the full color 3270 protocols. It does not support 3179G bit-mapped graphics (GDDM).
x3270 supports the APL character set and several international character sets. Many APL and international symbols are entered from the keyboard using the "Compose" key and combinations of other keys.