Tun Emul

Customizable Terminal Emulation

The Tun Emul module provides terminal emulation for more than 30 host types, including IBM ® 3270 and 5250 - as well as full 3287 and 3812 printer support - HP ®, DEC ® VT, SCO ® Unix, and others.

For PC-to-Host or multi-user Windows

Available for either PC-based or Microsoft ® Windows ® Server with Remote Desktop Services implementation, Tun Emul provides critical host access to all types of users - from green -screen power users to novices requiring limited functionality.

Administrators use the powerful customization tools included with Tun Emul to add background colors, graphical toolbars and function-key panels, mouse support, and hot spots. Familiar Windows utilities like copy/paste also help create seamless Windows-style host integration.

Customization is easy for administrators. The Tun Emul tools include features like drag-and-drop keyboard mapping and over 340 programmable actions.

In PC environments, Tun Emul runs under Windows 10, 8 and 7. In multi-user Windows environments, Tun Emul is available on virtually any client device.


Esker's most popular terminal environments (3270/3287, 5250/3812, VT, HP, and others) are available ActiveX ® components. This technology allows users to access and integrate data from multiple, diverse hosts simultaneously within a single environment ― the Workspace ― enhancing efficiency and productivity.

Central Deployment for All Technology

Tun modules also feature central installation and system maintenance in PC-based implementations. Administrators install modules on the server and the Esker Deployer on client machines. At startup, the Deployer detects Tun components, reconfigurations, or upgrades on the server and retrieves them to the client.

Esker thin-client technology extends connectivity to non-Windows resources and applications via Microsoft Windows Server with Remote Desktop Services. With Tun Emul for multi-user Windows, organizations benefit from centralized installation and administration, multi-user load balancing, lower software and maintenance costs, and unrivaled host access from virtually any client.


  • SSH (Secure Shell)
  • TLS (Transport Layer Security)
  • SSL (Secure Sockets Layer)
  • SFTP (Secure File Transfer Protocol)
  • SCP (Secure Copy Protocol)
  • X.509 certificates


  • 133 MHz or higher Pentium-compatible CPU.
  • 128 MB RAM and 60 MB of disk space.
  • Microsoft Windows with latest Windows update:
    • Windows ® 10 32-bit and 64-bit.
    • Windows ® 8 and 8.1 32-bit and 64-bit
    • Windows ® 7 SP1 32-bit and 64-bit
    • Windows Server ® 2012 and 2012 R2
    • Windows Server ® 2008 R2 SP1
  • In case of installation on Microsoft Windows Server with Remote Desktop Services, sufficient memory and disk space should be available.

Technical specifications

Productivity tools

  • Multiple Document Interface (MDI) Workspace with dynamic font scaling.
  • HotSpots and Hotlists.
  • Graphical and configurable keyboard mapper.
  • Menu and toolbar customization with pre-configured emulation executables.
  • Graphical screen configuration with full color support.
  • Floating or dockable function-key panels with graphical editor.
  • Copy and paste.
  • Screen printing.
  • Customizable character tables (national character sets).
  • Macro-language: Esker script, VBScript, and JScript ® including a macro recorder with password encryption and full-featured debugger
  • Online help

Synchronous terminal emulations

  • Emulations supported:
    • 3270 models: 3278 display (models 2, 3, 4, 5); 3279 display (models 2A, 2B, 3A, 3B).
    • 3270 printer: 3287 supporting SCS (LU1), DSC (LU3), transparent modes, and basic PCL.
    • 5250 models: 3179-2, 3296-A1, 5251-11, 5291-1, 5292-2, 3180-2, 3477-FC, 3477-FG.
    • 5250 printer: 3812 in SCS (LU1), transparent modes, host print transform.
  • Connectivity: TN5250, TN5250E, TN3270, TN3270E; native connections to Microsoft Host Integration (SNA) Server and intraNetWare for SAA gateway.
  • HLLAPI support (3270 emulation)
  • Support of APL characters, OIA toolbar status.
  • Extended attribute support (3270 emulation).
  • Multiple IND$FILE file transfers with host data set browsing (3270 emulation).
  • Enhanced firewall support via NVT mode (5250 emulation).
  • Euro character support.
  • Eastern European character set support.

Asynchronous terminal emulations

  • Emulations supported:
    • Hewlett-Packard ® HP 2392A, 2394, 700/92, 700/94, 700/96, 700/98.
    • DEC VT 52, 100, 220, 320, 420, 520.
    • SCO ® ANSI and ANSI
    • IBM 3151 and HFT.
    • Bull ® DKU 7102/7202 (SDP, VIP modes).
    • Wyse ® 50 and 60, Unisys ® TO300, Philips ® TM266, Minitel ® , Siemens ® BA80-08 and 97801, Linux ® console, Interactive Unix console AT386, Alcatel ® APX AT300, Fortune FT, Data General ® Dasher D412
  • Connectivity: TCP/IP (WinSock), SSH, NVT/IPX, Int 14h, Int 6Bh, serial connections (COM1-COM32), modem auto-dial, TAPI support for modem.
  • Documented API: with 30 objects described
  • 350 configurable actions (e.g., function keys, control codes, escape sequences, character sets, etc.)
  • Euro character support (VT, SCO, IBM 3151).
  • File transfer: X, Y, Z modem, Kermit, RTUNPLUS.
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