The FarSync X25 T4Ue PCIe card provides 4 high performance X.25 communications lines for Linux and Windows systems.
Overview
The FarSync X.25 T4Ue product is a high quality X.25 solution for business, government and military applications, it has been developed to provide high performance, versatile X.25 connectivity for Linux and Windows systems.
The PCIe card will support 4 X.25 lines at speeds to over 2.048 Mbits/s. The highly flexible universal network connector supports RS232, X.21, RS530, RS449 and V.35 network interfaces.
Features under Linux:
- The T4Ue card installs seamlessly as a plug and play device under the popular Linux 32 and 64 bit distributions. The card supports Linux kernel from 2.6.12 and onwards in 32 and 64 bit formats, including the leading distributions supplied by Red Hat, SuSE, CentOS, Ubuntu, Debian, Fedora, Slackware and more. SMP (multi-processor) systems are supported. Configuration is by a Java based GUI.
- There are APIs to the X.25 layer, a Sockets based interface and a Java API. There
is also an API to the ISO Transport layers (ISO 8073 – connection oriented). - IP over X.25 support is included permitting TCP/IP operation over an X.25 network.
- XOT (X.25 over TCP/IP) support is available as an option, using the same API’s as X.25. XOT can operate at the same time as X.25.
- Up to 254 connections per line are supported as standard or up to 4095 connections using the FarSync
X25 High Capacity Pack. - FarSite is committed to supporting the FarSync X25 T4Ue on new versions of Linux and Linux kernels as they are released. The source code for the driver and the libraries for the API are supplied with the product, allowing rebuilding by the end user for use with almost any of the current or future Linux variants. The driver supports both big-endian and little-endian memory storage formats.
Features under Windows:
- The T4Ue card installs seamlessly as a plug and play device under Windows 10, 8, 7, Vista, Windows Server 2016, 2012 and 2008. 32 and 64 bit Windows operating systems are supported.
- The X.25 software has a host of features including ISO Transport (classes 0 to 3), support for OpenFT FTAM, a WinSock2 compliant Sockets API, a Java API and a LAPB layer 2 (HDLC) that is also directly accessible by its own API. The Sockets API is also accessible from .NET applications.
- Up to 4095 connections can be supported using the FarSync X25 High Capacity Pack or 254 per line as standard.
- IP over X.25 support is included permitting TCP/IP operation over an X.25 network.
X.25 Developers Toolkit: A comprehensive Developers Toolkit for development using APIs to X.25 and ISO Transport is included with each product covering Linux and Windows. In addition, the Windows product has a toolkit for the LAPB API. A multi-port Line Monitor and a Line Statistics application are also supplied.
Watch our informative video about our X.25 products
Typical Applications
The FarSync X25 T4Ue card is suitable for connection to all types of X.25 networks, X.25 over the ISDN D channel and leased lines. Typical applications include:
- Private X.25 networks such as Lottery, Police, Customs, Military, Fishery, Financial, Government and Airline
- E-Commerce gateways for credit verification
- Mixed X.25 and IP networks
- SMS message gateways
- Billing and Mediation
- FTAM access
- X.400
- PC/Server based X.25 switch and an XOT Option
The card is compatible with all public X.25 networks, such as Datex-P, BT X.25 Direct, Eirpac, Austpac, Transpac and Itapac to name just a few.
FarSync X25 T4Ue – Hardware Details
The FarSync X25 T4Ue 4 line card runs an AMD processor with SRAM and an embedded HDLC controller connected to the Server/PC through a PCIe bus.
Network Interfaces
The 4 line multi function drivers support X.21 (V.11), V.35, RS232 (V.24, X.21bis), RS530 (EIA530, RS422), RS449 (RS422), network interfaces, all soft configurable and ESD protected from static charges. Line speeds to over 2.048 MBits/s are supported.
Clock Generation
External (line generated) clocking is supported. The T4Ue also supports card generated clocks speeds from 9600 baud to 8.192 Mbits/s, each line can be set to a different speed.
PCIe Bus Specification
The FarSync X25 T4Ue card is suitable for systems with a PCI express x1 (or higher) slot, covering single processor and multi-processor systems. The card is PCI Express Base Specification Revision 1.0a compliant.
Multiple Cards
The drivers supplied with Windows and Linux allow large numbers of lines to be supported by the installation of multiple FarSync X25 T4Ue cards in a Server. The card limit is only dependent on the PCIe slot count and resources available in the host Server.
TCP/IP over X.25
The IP over X.25 support is included as part of the FarSync X25 T4Ue product and is integrated into Linux and Windows.
Linux Features: IP over X.25 support complies with RFC 1356 (IP over X.25). Higher level protocols that run over IP including TCP, UDP, HTTP and FTP are supported.
Windows Features: The IP over X.25 support complies with RFC 1356 (IP over X.25), for single and multiple X.25 destinations. Higher level protocols that run over IP including TCP, UDP, HTTP and FTP are supported.

See further details about how IP over X.25 works
APIs and X.25 Developers Toolkit
Application developers have a choice of APIs for X.25 and ISO Transport. An API selector guide is provided to assist the developer in choosing the most appropriate interface. The comprehensive Developers Toolkit is included with the product.
X.25 Developers Toolkit and API details
FarSync XOT Extension option
For Linux the XOT extension allows applications using the same API to transmit data over XOT (X.25 over TCP/IP). TCP/IP is normally routed over Ethernet on PCs and Servers. The XOT support is compatible with FarSite’s FarLinX X25 Gateway and also other manufacturers XOT products. The XOT and X.25 interfaces can be used simultaneously.
The FarSync XOT Extension for Linux should be ordered at the same time that the FarSync X25 card is purchased, although a retrofit is possible.
Notes:
There is also FarSync XOT Runtime software for Linux available that allows XOT to run over the PCs standard TCP/IP connection such as an Ethernet card.
For Windows there is FarSync XOT Runtime software for Windows available that allows XOT to run over the PCs standard TCP/IP connection such as an Ethernet card.
FarSync X.25 High Capacity Pack option
An optional high capacity pack is available for the FarSync X25 T4Ue. The FarSync X.25 High Capacity Pack allows up to 4,095 simultaneous connections to be made; a huge increase from the standard 254 on each line. The expanded capacity applies to SVC, PVC and ISO Transport connections.
Customer applications developed to use the standard X.25 Sockets API are compatible with the FarSync X25 High Capacity Pack.
The FarSync X.25 High Capacity Pack is available for Windows and Linux, it should be ordered at the same time that the FarSync X.25 T4Ue is purchased although a retrofit upgrade is possible. One FarSync X.25 High Capacity Pack is required per card. See Order Information.

Configuration
For both Windows and Linux configuration is by a GUI configuration application, rapid installation and easy configuration are key features of the product. See sample screens below.
The X.25 line can be reconfigured and restarted without reloading the software.
Many of the parameters such as DTE / DCE selection are determined automatically. Selecting the line speed by default automatically sets suitable timer and retry values. An advanced tab permits users to exactly specify the configuration of the line if necessary.
Cables
The cable and connector configurations available for the FarSync X25 T4Ue are described in the FarSync product range and compatible cables table.
Crossover cables or DTE to DCE conversion cables also sometimes referred to as null modem cables, are also available.
Packaging
The X.25 software firmware, drivers, utilities and the X.25 Developers Toolkit are all included on the CD-ROM supplied with the FarSync card. Cables are ordered separately.
The CD-ROM supplied with the FarSync X25 T4Ue includes:
- Drivers for Linux, Windows 10, 8, 7, Vista, Windows Server 2016, 2012 and 2008
- Numerous example applications with source code
- Documentation for all the APIs in Adobe PDF format
- Source code for Linux drivers and API Libraries
- Network monitor and various useful utility programs
New releases of the software with enhancements and fixes are made available for free download from the Download page in the Support section of this web site.
Operating systems supported | Windows 10, 8, 7, Vista, Windows Server 2016, 2012 and 2008.
Linux distributions supplied by Red Hat, SuSE, CentOS, Ubuntu, Debian, Fedora, Slackware and others with kernel versions 2.6.12 and onwards. |
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Linux Kernel support | All sub versions of kernel releases from 2.6.12 and onwards. The products may operate successfully with earlier versions of the kernel but no specific testing has been undertaken by FarSite. | ||
SMP (Multi-Processor Systems) | The software has been designed for and tested on SMP Servers | ||
32 and 64 bit systems | The FarSync X25 T4Ue can be used on 32 and 64 bit systems under Windows and Linux and 32 and 64 bit applications | ||
X.25 Features | |||
X.25 CCITT compliance | 1980, 84 & 88 | ||
DTE/DCE operation | Both and Automatic detection and selection | ||
Maximum SVCs (all types) | 254 sessions on each line, any mix of bothway, incoming and outgoing 4,095 sessions using the High Capacity Pack, any mix of bothway, incoming and outgoing |
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Maximum PVCs | 254 sessions on each line 4,095 sessions using the High Capacity Pack |
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Maximum simultaneous connections | 254 connections on each line 4095 connections with the High Capacity Pack |
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Data Packet size range | 0 to 4096 bytes | ||
Data packets per second throughput | More than 2000 pps | ||
X25 facilities supported | Reverse charging, Closed User Group (CUG), Network User Identifier (NUI), Fast Select, Packet and Windows size negotiation, Extended sequence numbering (128), Throughput Class Negotiation. | ||
Types of network connection | X.25 packet switch, leased line, dial up (X.32 and dial on DTR) | ||
Accessible via API | Three APIs, a Sockets based interface, a Java API and a legacy NCB API. | ||
IP over X.25 | Supported, complies with RFC 1356 | ||
X.25 switch | X.25 Switch daemon available on Linux for free download for use with the FarSync X25 T4Ue | ||
XOT Option Features
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XOT Specification | Complies with RFC 1613 – X.25 over TCP (XOT) | ||
Maximum XOT connections | 4,095 on Linux, 4,095 on Windows | ||
Maximum SVCs and PVCs | 4,095 on Linux, 4,095 on Windows (any mix of SVCs and PVCs) | ||
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. |
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Accessible via API | Two APIs, a Sockets based interface, a Java API | ||
ISO Transport Features | |||
Supplied with the X.25 software | Included with both the standard product and the High Capacity Pack | ||
Standard supported | ISO 8073 (connection oriented) | ||
Classes supported | Classes 0, 1, 2 and 3 | ||
Negotiation between classes | Yes | ||
Simultaneous transport connections | 254 sessions on each line, 4,095 sessions using the High Capacity Pack |
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TPDUs in a NSDU | 1 | ||
Accessible via API | Yes | ||
Developers Toolkit
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X.25 Developers Toolkit and API functional summary | |||
Card type and PCIe Specification | AMD processor with SRAM and quad port synchronous controller, PCIe bus compliant with PCI Express Base Specification Revision 1.0a, x1 (single lane), Bus mastering card |
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Physical characteristics | Short card (height 107mm, length 167mm) | ||
Multiple cards | Yes, the card limit is only dependent on the resources available in the host Server | ||
Network connections supported | X.21 (V.11) – DTE DB15M type connector, V.35 – DTE M34M type connector, RS232 (V.24, X.21bis) – DTE DB25M type connector, RS530 (RS422) – DTE DB25M type connector, RS449 – DTE DB37M type connector |
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Link speed range | RS232: 75 baud up to 128 Kbits/s X.21, V.35, RS530, RS449, RS422: 75 baud to over 2.048 Mbits/s |
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ESD protection | Yes, Littelfuse high speed ESD and over-voltage protection | ||
LED line status indicators | 4 line status | ||
Approvals and Compliance | EN55022 class B, CE, FCC class B, RoHS2, REACH | ||
Power requirements | < 1.75 A @ +3.3v < 10mA @ +/- 12v < 6 watts |
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Operating Temperature Range | 0 to 60°C ambient air temperature. | ||
MTBF | 229,044 hours – calculation based on Bellcore Method 1 Case 3, 40 deg.C ambient, 15 deg.C case temperature rise above ambient. | ||
Line clocking (external and card generated) |
Card generated and External supported Card generated clock range 9,600 baud to 8,192 Mbits/s. No special cables are required to use card generated clocks on RS232, X.21 and RS530 (RS422). Card generated clocking is supported on V.35 and RS449 with the use of cables designed for card generated clocks. |
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Cable type compatibility | Cables are ordered separately see the FarSync product range and compatible cables table for a list of cables available. | ||
Warranty | 5 years free warranty. |
Product Name | Description | Product Code |
FarSync X25 T4Ue | Intelligent 4 port X.25 PCI Express card with X.25 Software and the X.25 Developers Toolkit for Windows and Linux included. | FS6450 |
Software Options
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FarSync X.25 High Capacity Pack for Windows | Upgrade to the standard Windows FarSync X.25 software that allows up to 4095 simultaneous sessions | FS9504 |
FarSync X.25 High Capacity Pack for Linux | Upgrade to the standard Linux FarSync X.25 software that allows up to 4095 simultaneous sessions | FS9505 |
FarSync XOT Extension | An optional upgrade to add XOT (X.25 over TCP/IP) with FarSync X.25 cards on Linux. A FarSync X25 card must be purchased with this product. |
FS9508 |
FarSync XOT Runtime – Windows | XOT (X.25 over TCP/IP) support on Windows | FS9511 |
Cable Options
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For cable types supported by the FarSync X25 T4Ue see the FarSync X25 product range and compatible cables table |
Microsoft, Windows, and the Windows logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries.
All trademarks and registered trademarks are acknowledged.
Changes are periodically made to the information herein; these changes will be incorporated into new editions of the publication. FarSite Communications may make improvements and/or changes in the products and/or programs described in this publication at any time.