November 19

5 comments

Where can I Download Free IBMi (AS400) 5250 Terminal Emulator?

By NickLitten

November 19, 2020

IBM i, as400, iseries

What is a 5250 Terminal Emulator?

In a previous blog about 5250 Emulators:

The IBM i System (aka i5 aka iSeries aka AS/400) uses something called 5250 to stream its data to a terminal, often called a green screen. You’ve seen these clunky old terminals in black and white sci-fi movies – well we still use them. Kind of. But we use terminal emulators (software that emulates the functions of those old terminals) to type commands into a command-line interface using windows/linux/mac whatever.

Me. A Decade Ago.

Before we get to evaluating 5250 Emulators – both premium and opensource – let’s talk about what this thing is:

What is a 5250 Terminal?

A long time ago, in a galaxy far far away, long before networks, internet, and clouds ( the virtual ones not the big white fully ones) we used to connect to giant creamy supercomputers, like the System/3x and AS/400, using a Twinax cable.

These miles of cables running around offices, let users sign on and use a central computer before our modern networks were in common use.

The old CRT Screens were most commonly green text on a black background:

As400 iseries ibm i 5250 emulator 1
IBM 5251 Terminal

As years went by, these old clunky terminals were lightly modernised, but remained predominantly green on black:

As400 iseries ibm i 5250 emulator 2
IBM 3486 Twinax Terminal

This next generation even had a… wait for it… super modern colour screen option:

Ibm 5250 screen terminal
5250 Terminal with Color

What is a 5250 Emulator?

With the 1980’s came the new range of Personal Computer’s. They ran this thing called DOS, or sometimes the new and fancy Microsoft Windows. These machines would have a physical interface card, allowing them to connect to main AS400 using Twinax:

As400 iseries ibm i 5250 emulator 3
Twinax Card with adaptor

Then we could install the DOS/Windows Software which would let your PC application emulate a physical 5250 Terminal. With this card installed, we could now use a desktop application that looks and acts like a real physical 5250 terminal.

This software is what is commonly called “5250 Emulation”

It would display the same thing that you would see on a physical terminal in a window on your desktop:

5250 emulator
5250 Emulation Screen Example

So, the 5250 Emulator was born!

Over the years lots of different companies have released their own version of this 5250 emulator software, letting users work with their AS400 system, the new iSeries system and as these were replaced by the current IBM i Power System. This new breed of 5250 emulators has continued to improve and expand its abilities.

Today’s 5250 Emulators commonly running on just about any platform from Windows to Mac to Android. Modern 5250 emulators let you quickly sign on to any IBM i system anywhere in the world.

Look at some Free Emulators

Click here to watch some emulators be downloaded, installed and reviewed:


Are you asking which are the best PREMIUM 5250 Emulators vs the best FREE 5250 Emulators?

  • What is the protocol we use here to connect for as400 systems from tn5250 terminal ?
    Is it tell net with TCP/IP .
    Cant we use any other protocol to connect securly ?

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