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FarSync XOT Runtime – XOT (X.25 over TCP/IP) software for Linux

FarLinX XOT network wtext v1.1t 3

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The FarSync XOT Runtime software provides an API to support applications that previously required an X.25 interface to use XOT instead.


FarSync XOT Runtime has been developed to provide high performance and very reliable XOT connectivity for Linux. FarSync XOT Runtime for Linux inter-operates with the FarLinX X25 Gateway , FarSync XOT Runtime for Windows and other third party XOT devices, which can allow a complete X.25 network to be replaced by TCP/IP including IPv6, eliminating hardware and costs just leaving a short X.25 connection to the host. The diagram above illustrates this.

There are 2 main APIs, a Sockets based interface and a Java API. There is also an APIs to the ISO Transport layers (ISO 8073 – connection oriented). A comprehensive Developers Toolkit is included with the product. The API is compatible with the FarSync X.25 APIs.

FarSync XOT Runtime is supported on Linux kernel versions from 2.6.12 onwards, including the leading distributions supplied by Redhat, SuSE, Mandriva, Debian, Ubuntu, Slackware, Fedora and others. Multi-processor, 32 and 64 bit systems are supported. FarSite is committed to supporting the FarSync XOT products on new versions of Linux as they are released. The source code for the driver and the libraries for the API are supplied with the product.

New features with version 3.2

  • Major speed improvements in data throughput, particularly using large numbers of sessions, now up to 160 Mbps
  • Full decode X.25 and higher level protocols available using Wireshark protocol analyser application
  • Private XOT facilities now passed to the application
  • PVCs greater than 256 now supported
  • Epoll supported
  • Improved API documentation

Customers running earlier versions can upgrade to 3.2, more info.

Watch our informative video about our X.25 products

Typical Applications

The FarSync XOT Runtime is suitable for connection to remote systems running XOT, typical applications include:

  • XOT replacements for X.25 networks
  • E-Commerce gateways for credit verification

Developers Toolkit

The Developers Toolkit is included free with the FarSync XOT Runtime product and features:

  • Documented working C and Java source sample programs. Source code from these samples can be used to fast-track your development process.
  • Comprehensive API manuals with function call definitions and helpful advice on the best way to utilise the various interfaces.
  • Source code for the drivers and API libraries.
  • Line monitoring analyser for the X.25/XOT traffic
  • Free email and telephone assistance to application developers.

APIs for Application Development

For application developers needing to access XOT there is a choice of a Sockets API or a Java API. Both APIs interfaces may be used simultaneously by different programs if required. API manuals and many example applications are included in the Developers Toolkit for both types of interface. The APIs are compatible with the APIs for FarSync X.25 cards.

Sockets API

The Sockets interface provides a programming language independent high level connection orientated interface with access to a comprehensive set of X.25 features. The FarSync Sockets implementation is compatible with the BSD Sockets interface. The API is compatible with the Sockets API for the FarSync X25 cards. Multi-threaded applications are supported.

Java API

The Java API allows applications written in Core Java Software (J2SE) and Enterprise Java Software (J2EE) easy access to the functions and features of FarSync XOT. Full documentation and sample applications are provided.

ISO Transport API

The interface provides a programming language independent, connection orientated interface controlled by command blocks. Full access is available to ISO Transport (ISO 8073 – connection orientated) Classes 0 to 3.

Further details on the XOT/X.25 Developers Toolkit and APIs.


XOT Configuration application

Configuration is by a Java and XML-based GUI configuration application. A typical screen is shown on the right, see a larger sample.

Text file based configuration is also available if required.


Installation scripts adapt to install the software on the major Linux distributions and a manual install option is available using the scripts as a guide, available on the CD-ROM.

Source code is available as a .tar.gz.

A comprehensive configuration guide, commands reference and configuration examples are provided as part of the HTML documentation pack.


A line monitor utility is included, this can display data sent over the XOT lines at the frame and packet level, it is invaluable when developing and debugging applications. A status utility allows display of the channel connection status and statistics of user data, packet and frame types.


The XOT software, utilities and the Developers Toolkit are all included on the CD-ROM. New versions of the XOT software are made available for download see the download page.

Technical Specifications
Operating systems supported Linux distributions supplied by Redhat, SuSE, Mandriva, Debian, Ubuntu, Slackware, Fedora and others. FarSite is committed to supporting the FarSync XOT Runtime on new versions of Linux as they are released. If you want to run on a Linux VM then Contact us.
Linux Kernel Support All sub versions of kernel releases from version 2.6.12 and onward. The product may operate successfully with earlier versions of the kernel but no specific testing has been undertaken.
Multi-processor systems The software has been designed for and tested on single and multiprocessor servers
64 bit systems Designed for and tested on single and multi-processor) Servers, 32 and 64 bit systems.
TCP/IP IPv4 and IPv6
XOT Features
XOT Specification Complies with RFC 1613 – X.25 over TCP (XOT)
Maximum XOT connections 4,095
Maximum SVCs and PVCs 4,095, any mix of SVCs and PVCs
Data Throughput up to 160 Mbits/s
Data packets size range 0 to 4,096 bytes
OOB (Out of Band) data Supported for Interrupts, Resets and the D bit
X25 facilities supported Closed User Group (CUG), Network User Identifier (NUI), Fast Select, Packet and Windows size negotiation, Throughput Class Negotiation.
Accessible via API Two APIs, a Sockets based interface and a Java API.
ISO Transport Features
Standard supported ISO 8073 (connection oriented)
Classes supported Classes 0, 1, 2 and 3
Negotiation between classes Yes
Simultaneous transport connections Up to 4,095
Accessible via API Yes, NCB API
Developers Toolkit
XOT API Sockets API, easy to use, provides access to XOT features, recommended for new developments.

Java API, allows easy access to XOT from Java applications.

ISO Transport API NCB based API providing access to all the features of the ISO Transport support. Can operate simultaneously with access to the XOT layer.
API reference manuals Manuals: XOT (and X.25) Sockets API, ISO Transport API and Java API documentation.
Sample programs Included, large number of example applications are available for driving the various APIs.
Source code Included for drivers, the API libraries and sample C and Java applications.
Order Information
Product Name Description Product Code
FarSync XOT Runtime for Linux XOT (X.25 over TCP/IP) Runtime software version 3.2 for Linux with Developers Toolkit FS9506
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