b3270 Introduction

b3270 is the back end of a IBM 3270 terminal emulator. It can be used to communicate with any IBM host that supports 3270-style connections over TELNET. It can also communicate with hosts that use line-by-line ASCII mode to do initial login negotiation before switching to full-screen 3270 mode.

b3270 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; b3270 understands extended field orders but does not implement some of the extended attributes (outlining, extended validation, etc.). It does not support 3179G bit-mapped graphics (GDDM).

b3270 supports the APL character set and several international character sets. Many APL and international symbols may be entered by their X11 symbol names.

b3270 communicates with a front end (usually a Graphical User Interface) using XML over its standard input and output. b3270 handles the 3270, TELNET and TLS protocols, while the front end handles user interactions.