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Using x3270 with an IBM AS/400

There have been a few questions asked on about accessing an AS/400 “green screen” display from Unix. This page describes how I had it set it up very nicely under Linux using the x3270 terminal emulator.

My environment was:

(Since I first wrote this document, a few links to it have appeared on various web pages, and I’ve started then stopped maintaining x3270 for Debian.)


The first thing to do is to get x3270 compiled, installed and configured to connect to the AS/400 system. This is all fairly well covered in x3270’s documentation, so I won’t expand on it here.

When you connect to the AS/400 using x3270, you will (surprise!) be using a 3270 data stream, which the AS/400 converts to a 5250 data stream for you. Recent versions of x3270 emulate a 3279 device, which has the enhanced features necessary for all the colours and highlighting to be displayed. In fact, I found the effects to be closer to what is described in the DDS Reference than any other PC emulator.

System Request support

A problem with all official releases of x3270 up to, is that there is no way to use System Request to interrupt a display that has the keyboard locked. The new TN3270E RFC defines the 3270 Attn function as sending a telnet ‘Interrupt Process’ code, which is not what x3270 normally sends. It turns out that the AS/400 supports this code for System Request.

For System Request to work properly, I recommend compiling the latest version of x3270.

Configuring for AS/400

All the configuration you need should be taken care of by my .x3270pro file. Make sure there’s nothing you want to keep in your current one, then drop mine in your home directory. If you’re the latest version of x3270, use the .x3270pro patched file instead. Then start up x3270 and try it!

This is what the file actually does:



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