Technical Spec´s XOT Software Windows *

© Farsite Communication Ltd. • 2012


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

A comprehensive Developers Toolkit is included with the product.

The API is based on Sockets (compliant with Winsock2) and is compatible with the Microsoft defined X.25 Sockets API. Applications written to use the Microsoft X.25 Sockets API, FarSync X.25 cards and some other commonly used X.25 cards will work with the FarSync XOT product without change.

The API supports standard AF_ISO / ISOPROTO_X25 sockets used by a number of applications, such as MS-Exchange. It also supports the AF_X25 address family used by the applications written to use FarSync X.25 products.

Applications developed in most programming languages, including Visual Basic, Delphi, C++ and .NET applications, can use the Sockets API to FarSync XOT, and there is a Java Extension API supplied to provide access from Java applications.

Both X.25 SVCs and PVCs are supported with a maximum of 4096 simultaneous connections.

FarSync XOT Runtime is supported on Windows 7, Vista, XP, Server 2003 and Server 2008. Multi-processor, 32 and 64 bit systems are supported. For 64-bit applications support is planned for a future release.

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 it 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.
        • Free email and telephone assistance by the FarSite Engineers group 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.

Winsock2 API

The WinSock2 compliant sockets interface provides a programming language independent high level connection orientated interface with access to a comprehensive set of XOT / X.25 features. The API is compatible with the Sockets API for the FarSync X25 cards and the Microsoft X.25 Sockets API standard. Address families AF_ISO / ISOPROTO_X25 and AF_X25 are supported. XOT-specific additions to the API provide access to XOT parameters such as the IP address for the remote XOT node.

Java API

The Java API for FarSync X.25 is supported on XOT and allows applications written in Core Java Software (J2SE) and Enterprise Java Software (J2EE) easy access to the functions and features of FarSync XOT.

Installation and Configuration

The FarSync XOT Software is simple to install and use immediately. Configuration is required to map the X.25.
Destination Address to the IP Address of the remote host or node, except when the application is able to supply such information itself via the XOT-specific features of the API.

There is a text file mapping from X.25 parameters to IP Addresses.

Monitoring XOT Activity

The widely used line monitoring utility Wireshark can be used to monitor and decode the FarSync XOT sessions providing a comprehensive analysis of line traffic required by developers and systems installers.


The XOT software and the Developers Toolkit are all included on the CD-ROM.

Technical Specifications

Operation Systems supported

Windows 7, Windows Vista, Windows XP, Windows Server 2003, Windows   Server 2008

64 bit and   multi-processor systems

Designed for, and tested on single and multi-processor) Servers, 32   and 64 bit systems; API support for 32-bit applications.

XOT Features

XOT Specification

Complies with RFC 1613 - X.25 over TCP (XOT)

Maximum XOT connections

Up to 4,095

Maximum SVCs and PVCs

4,095 SVCs and 4,095   PVCs

Data Throughput


Data packets size range

0 to 4,096 bytes

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.

Developers Toolkit


Sockets API, easy to use, provides access to the XOT   features
  Java Extension API, allows easy access to XOT sockets from Java applications

API reference manuals

Manuals: XOT (and X.25) Sockets API and Java API documentation.

Sample programs

Included, large number of example applications are available.

* All specifications are subject to change