The FarSync Flex X.25 USB adapter has been developed to provide high performance X.25 communications for Linux and Windows systems.
Overview
The FarSync Flex X.25 adapter 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 bus powered V3* version of the USB adapter will support an X.25 line at speeds of up to 2.048 Mbits/s. The highly flexible universal network connector supports RS232, X.21, RS422, RS530, RS449 and V.35 network interfaces. Line signal encoding modes NRZ, NRZI, FM0, FM1, Manchester Encoding or Conditioned Diphase can be used.
*The FarSync Flex V3 hardware used in the FarSync Flex X25 superseded the V2 in July 2018, it is a plug in replacement. The V3 is 100% compatible (updated driver required) with the additional features of a wider operating temperature range and higher operating speed. The FarSync Flex V2 is no longer available due to part obsolescence.
Features under Linux:
- The Flex adapter installs seamlessly as a plug and play device under the popular Linux 32 and 64 bit distributions. The USB adapter is supported on Linux kernel versions 2.6.12 and later in 32 and 64 bit formats, including the leading distributions supplied by Redhat, SuSE, Debian, Ubuntu, 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 are supported as standard or up to 4095 connections using the FarSync
X25 High Capacity Pack. - FarSite is committed to supporting the FarSync Flex X25 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 Flex adapter 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. Multiple Flex’s can be installed.
- 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 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. 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 Flex adapter 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
- Lottery Terminals
- ATM connections
- X.400
The adapter 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.
Key Features
The intelligent FarSync Flex X.25 has been designed for easy installation and to provide high performance in a variety of environments. The Flex adapter uses an ARM processors with Flash for the on board code.
- 254 simultaneous SVC and PVC virtual connections or 4095 per port using the High Capacity Pack
- XOT (X.25 over TCP/IP) support available as an option on Linux
- Over 2,000 X.25 packets per second
- Line speeds of up to 2.048 Mbits/s
- Network interfaces for X.21 (V.11), V.35, RS232 (V.24, X.21bis), RS449, RS530 (EIA530, RS422)
- Line signal modes NRZ, NRZI, FM0, FM1, Manchester Encoding or Conditioned Diphase up to 2.048 Mbits/s
- USB 2.0 high-speed mode (480mb/s) and 1.1 compatible
- High efficiency, USB Bus powered, energy saving design
- Internal and external line clocking
- Dual bank flash for secure in field upgrades and previous system restore capability
- Optional mounting brackets (factory fitted)
Configuration
configuration of a Flex for X.25
configuration of a Flex
For both Windows and Linux configuration is by a GUI configuration application, see a samples screens below.
The X.25 line can be reconfigured and restarted without reloading the software and the Flex supports hot plug in.
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.
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
TCP/IP over X.25
The IP over X.25 support is included as part of the FarSync Flex X25 product and is integrated into Linux and Windows versions.
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
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 is available under product code FS9508, it 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 PC’s 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 Flex X25. The FarSync X.25 High Capacity Pack allows up to 4,095 simultaneous connections to be made, a huge increase from the standard 254. 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 under product code FS9504 for Windows and FS9505 for Linux, it should be ordered at the same time that the FarSync Flex X.25 is purchased although a retrofit upgrade is possible. One FarSync X.25 High Capacity Pack is required per Flex device.
Cables
The cable and connector configurations available for the FarSync Flex X25 are described in the FarSync Flex X25 product range and compatible cables table. Crossover cables, sometimes referred to as null modem cables, are also available.
Packaging
A download product id is supplied with the product to allow download of the X.25 software firmware, drivers, utilities and the development toolkit. Cables are ordered separately.
The downloadable software includes:
- Drivers for Linux, Windows 10, 8, 7, Vista, Windows Server 2016, 2012 and 2008. 32 and 64 bit drivers are supplied
- Numerous example applications with source code
- Documentation for all the APIs in Adobe PDF format
- Source code for Linux drivers and API Libraries
- Various useful utility programs
New releases of the software are made available for free download from the Download page in the Support section of this web site.
Software Technical Specifications | |
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Operating systems supported | 32 and 64 bit versions of Windows 10, 8, 7, Vista, Windows Server 2016, 2012 and 2008.
Linux distributions supplied by Redhat, SuSE, CentOS, Mandriva, Debian, Ubuntu, Slackware, Fedora and others with kernel versions 2.6 or later. |
Linux Kernel Support | Sub versions of kernel releases from 2.6.12 and onward. |
SMP (Multi-Processor Systems) | Yes, the software has been designed for and tested on SMP Servers |
32 and 64 bit systems | The FarSync Flex X25 can be used on 32 and 64 bit systems under Linux and Windows and with 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, any mix of bothway, incoming and outgoing 4,095 sessions using the High Capacity Pack, any mix of bothway, incoming and outgoing |
Maximum PVCs | 254 sessions 4,095 sessions using the High Capacity Pack |
Maximum simultaneous connections | 254 connections 4095 connections with the High Capacity Pack |
Data Packet size range | up 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 | Yes, a number of different APIs to suit various requirements |
IP over X.25 | Supported, complies with RFC 1356 on Linux and Windows |
X.25 switch | X.25 Switch daemon available on Linux for free download for use with the FarSync Flex X.25 |
XOT Option Features | |
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. |
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, 4,095 sessions using the High Capacity Pack |
TPDUs in a NSDU | 1 |
Accessible via API | Yes |
Developers Toolkit | |
X.25 Developers Toolkit and API details | |
Hardware Technical Specifications | |
General | Intelligent USB adapter with ARM processor, dedicated RAM and dual bank Flash memory, Field upgradeable onboard firmware, USB Bus powered, USB 2.0 (high-speed – 480Mb/s mode) and 1.1 compatible, Network line connector: HD26 for connection of network cables Hot plug in supported |
Physical characteristics | Size: – Height 30mm, Length 126 mm, Width 62mm Material: Anodised extruded aluminium Weight: 190g 0.6 metre A to B type USB cable with screw in fitting into the Flex adapter |
Multiple adapters | Yes, typically 8 or more Flex adapters can be supported; the adapter limit is only dependent on the number of powered USB ports available. The FarSync Flex X25 can also be mixed with FarSync X25 T-Series cards |
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 |
Line Signals Modes | NRZ, NRZI, FM0, FM1, Manchester Encoding or Conditioned Di-phase to 2.048 Mbits/s |
Link speed range | RS232: up to 128 Kbits/s X.21, V.35, RS530, RS449, RS422: to 2.048 Mbits/s |
ESD protection | Yes, Littelfuse high speed ESD and over-voltage protection |
LED line status indicators | 1 line status |
Approvals and Compliance | EN55022 class B, CE, FCC class B, RoHS2, REACH |
Operating Temperature Range | –40 to 85°C ambient air temperature |
Power requirements | USB Bus powered, < 500 mA on full load, < 2.0 watt |
MTBF | 360,181 hours – calculation based on Bellcore Method 1 Case 3, 40°C ambient, 15°C case temperature rise above ambient. |
Line clocking (internal/external) | Both, Adapter generated clock range 9,600 baud to 2.048 Mbits/s on X.21, V.35, RS232, RS422, RS530 and RS449 |
Cable type compatibility | Cables are ordered separately see the FarSync Flex product range and compatible cables table lists the cables available |
Warranty | Free 5 year warranty |
Order Information | |||
---|---|---|---|
Product Name |
Photo |
Description |
Product Code |
FarSync Flex X25 | ![]() |
1 port synchronous USB Adapter with X.25 Software and developers toolkit. Includes the Flex hardware, USB cable, drivers, utility programs, documentation on CD-ROM and a quick start guide. * |
FS6100 |
FarSync Flex | Basic synchronous adapter, click for details * | FS4100 | |
* If you require the FarSync Flex for use with Nokia Siemens Networks LMT software then please contact us. | |||
Cable Options | |||
KCR1 | ![]() |
RS232 (V.24, X.21bis) and RS530 (EIA530, RS422) DTE cable. DB25M connector, same cable for both interfaces, 1.5 metres | FS6011 |
KCR1-DCE | RS232 (V.24, X.21bis) and RS530 (EIA530, RS422) DCE cable. DB25F connector, Same cable for both interfaces, 2 metres | FS6070 | |
UCX1 | ![]() |
X.21 (V.11) DTE cable. DB15M connector, 1.5 metres | FS6062 |
UCX1-DCE | X.21 (V.11) DCE cable. DB15F connector, 2 metres | FS6075 | |
UCV1 | ![]() |
V.35 DTE cable. M34M connector, 1.5 metres | FS6063 |
UX35C | ![]() |
V.35 special DCE cable. M34F connector, 1.5 metres. | FS6095 |
KC449 | RS449 (RS422) DTE cable. DB37M connector, 1.5 metres | FS6019 | |
Accessories | |||
Flex Mounting Kit | ![]() |
A pair of FarSync Flex mounting brackets. Can be retro fitted without opening the case. |
FS4901 |
Software Options | |||
FarSync X.25 High Capacity Pack for Windows | Upgrade to the standard Windows X.25 software that allows up to 4095 simultaneous sessions | FS9504 | |
FarSync X.25 High Capacity Pack for Linux | Upgrade to the standard Linux 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 |