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FarLinX Mini Gateway – A Compact X.25 / XOT Gateway

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Need to migrate from X.25 to TCP/IP?

We supply a range of TCP to X.25 Gateway's that also support XOT (X.25 over TCP/IP) and TCP/IP to X.25 data format translation and connection routing.

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The FarLinX Mini Gateway is the smallest member of the FarLinX Gateway range – it can handle your smaller scale single X.25 line to TCP/IP migration requirements. It offers many of the same features as in the larger FarLinX X25 Gateway range but at a lower price and in a more compact enclosure. The Gateway supports XOT to X.25 switching, X.25 to TCP data translation and connection routing, TCP to XOT, a Triple-X PAD, and a Host PAD. All this is easily managed from your browser. There are also daily activity logs with a selectable level of detail, automatically archived on a daily basis. The SNMP support provides alerts for a numerous different conditions including critical events such as line down and line up.

The more powerful FarLinX X25 Gateway range is more suitable where multiple and faster X.25 lines are used.

Key Features

  • TCP to X.25 data translation with a very wide variety of modes including: character streaming,
    RFC1006, Cisco RBP, APACS, ISO 8583, header stripping and parity conversion and many more
  • TCP ↔ X.25 and TCP ↔ XOT routing including: fixed routes, dynamic routing and PAD routing
  • Call routing between XOT (X.25 over TCP/IP) and the X.25 line
  • X.28 PAD option supporting Telnet and an async connection
  • X.25 Host PAD emulation support
  • LAN accessible X.25 line as a sharable remotely manageable resource
  • Choice of X.25 network interface connections: RS232 (V.24), V.35, RS422, RS530, X.21
  • 400 messages per second and up to 50 simultaneous connections (PVC, SVC)
  • Line Monitor (local or remote) to view X.25 traffic for easy network problem diagnosis
  • Optional support for TCP/IP authentication and data security using IPSEC
  • IP and IPv6 support
  • Browser graphical configuration, SNMP alerts for critical events and activity logging
  • Real time display of current connections, line performance, errors, connections and much more
  • Small rugged low profile all metal case, low power consumption

Watch our informative video about FarLinX Mini Gateway’s and other X.25 products

Typical Applications

  • Reduce line costs by replacing an expensive X.25 line with a TCP/IP connection and conversion to X.25 at
    each terminating node
  • Conversion of legacy X.25 connections and data for transfer over a TCP/IP network
  • POS Gateway to allow TCP/IP and X.25 based Point of Sale systems to interoperate
  • Replacing an X.28 PAD over X.25 with an X.28 PAD over XOT
  • FTAM or X.400 operation between TCP/IP and X.25
  • Conversation from TCP to XOT eliminating the need for X.25 at that location
  • LAN accessible and sharable X.25 port resource

Functional Overview – XOT and X.25 Switching

The FarLinX Mini Gateway provides a reliable means of routing connections between X.25 and XOT (X.25 over TCP/
IP). Connections can be routed between X.25/X.28 and XOT which is treated as another connection path. The connection routing module supports default routes, hunt groups, X.25 address translation, and routing commands with NUA wildcards for maximum flexibility.

Up to 50 SVC or PVC sessions can be handled simultaneously over XOT and the X.25 line.

FarLinX Mini Gateway's configured as an XOT Network

This configuration shows a complete X.25 network simulated by FarLinX Mini Gateway’s running XOT over an IP network (4 X.25 lines in this example but could be hundreds or thousands). This allows complete X.25 networks to be replaced while leaving hosts connected by X.25 to that network undisturbed.

Functional Overview – data packetization and routing between TCP and X.25 or XOT

The Gateway provides connection establishment and data packetization services to allow applications sending data over TCP/IP to interface to X.25 or XOT connected hosts. The Gateway provides routing facilities to select the appropriate Host from those available and maintains X.25 or XOT sessions to the Host as required.

Up to 50 SVC or PVC sessions can be handled simultaneously between TCP/IP and X.25 or XOT.

Diagram showing IP and X.25 Networks interconnecting using a FarLinX Mini Gateway

Example network configuration where the FarLinX Mini Gateway is used to
link between
the TCP/IP and X.25
networks to allow interconnection between the host and client computers connected to the networks

TCP to X.25 or XOT data translation functions

The Gateway supports a wide range of TCP to X.25 or XOT data translation and connection functions, these include:

  • Character stream
  • ETX terminated messages
  • Special character terminated messages (customisable)
  • Message header conversion – types available 2 or 4 byte ASCII or Binary length representation
  • Custom message header conversion
  • RFC1006 – ISO Transport Class 0 protocol data units, using the RFC-1006 encapsulation on the TCP connection
  • Cisco RBP – Record Boundary Preservation
  • X.25 Parity conversion – the Gateway performs any required parity adjustments and removal on the X.25 / XOT
  • POS protocols APACS, ISO 8583, HGEPOS plus CTL (Card Tech Ltd) – Requires the POS Firmware Option

Connection Routing and Address Mapping

The FarLinX Mini Gateway can support routes to hundreds of different X.25 / XOT hosts. Similarly, when using the
called X.25 address as the routing key, incoming X.25 / XOT calls can be routed to hundreds of different TCP/IP
When making connections to the X.25 network or XOT, the Gateway has the capability of mapping the source IP
address to a calling X.25 address, thus allowing the destination X.25 / XOT host to identify the connection source
The Dynamic routing options allow the X.25 address (NUA) and call parameters to be set by the remote application at
the time each X.25 / XOT connection is established. These modes allow X.25 packetisation information to be passed
to the application. Linux and Windows sample applications provided.
The main modes supported include:

  • Statically defined routing
  • XDRPD (eXtended Dynamic Routing Packetized Data) and DRPD – these formats allow TCP connected applications to dynamically setup and control the X.25 or XOT connection
  • X.25 Data Switching – allows X.25 devices to be interconnected via an IP network without the overheads associated with XOT
  • PAD Routing – PAD or Dynamic routing may be employed to allow the TCP client application to specify the X.25 call parameters

Functional Overview – PAD Features

X.28 Host Pad

The FarLinX Mini Gateway can be configured to act as an X.28 host PAD for remote terminals or applications connecting over X.25 and expecting a host that supports X.28. The host PAD sends X.28 PAD configuration commands over X.25 to the connecting terminals. The host PAD profile is configurable.

X.28 Triple-X PAD

Triple-X PAD (X.28, X.3 and X.29) support is included with the Gateway, and is accessible over TCP/IP via Telnet or using the single permanent async port. The connecting terminal is presented with a Triple-X PAD service and can be used to make X.25 connections over the physical X.25 line or via XOT connections to remote hosts. The initial PAD profiles for the async port and for the Telnet access are fully configurable.

Encryption over TCP/IP (IPSEC)

Available as an option at the time of ordering, the FarLinX Mini Gateway can be supplied with an IPSEC capability that can provide communications security in IP networks. This can be especially important when public Internet connections are used for part of the communications path.

IPSEC operates between a pair of devices. Each must know details of the remote device in order to authenticate communications and successfully encrypt/decrypt data being sent and received. In the case of the FarLinX Mini Gateway, the details of multiple partner Gateways can be configured. The pre-shared key used to authenticate is unique for each remote partner. Once authentication has completed an exchange of encryption keys takes place under the pre-shared key. The session key is used only for a single session.

FarLinX Gateway models without IPSEC can be supplied to any country. Models with IPSEC capability can be exported without a special export licence to some countries. Where IPSEC is required and the destination country is not on the pre-approved list, FarSite will apply for an export license for that customer. See Order Information for more details.


FarLinX X.25 Configuration

The Gateway is configured from a Browser – IE, Firefox and Chrome are all supported. Access to the configuration is secured through a user name and password.

The Configuration Application allows all the features of the Gateway to be managed. The majority of configuration changes to the Gateway are made dynamically so continuous operation of the Gateway can be maintained.
See a sample screen of the X.25 configuration on the right.

Configurations can be saved for later use.

System Upgrades

Upgrades to the firmware can be remotely and securely uploaded to the device to allow the latest revision firmware to be used. Rollback to a previous version is supported.

Statistics, Event Logging and SNMP


The gateway maintains a comprehensive set of statistics and activity counts. This information can be used to indicate the total loads on the Gateway and also to give early warning of line performance problems and even misconfigured systems elsewhere in the network.


All connections setup through the Gateway can be logged. The logs are automatically saved on a daily basis. Old logs can be displayed as required. Log events can also be routed to syslog to allow logging centrally.

The connection status of active connections / most recent connections / disconnections are displayed in a browser window.


The Gateway supports SNMP alerts with 3 configurable levels. Alerts can be issued for SVCs connecting and disconnecting, PVC errors, connection routing errors, line up and line down events and many more events.

Built in X.25 Line Monitor

The Gateway includes Line Monitor software installable from CD onto a Windows PC. This allows X.25 traffic to be recorded and displayed in real time. Multiple Gateways can be monitored simultaneously. Support to allow the popular Wireshark line monitor to record and display the X.25, TCP/IP and XOT line traffic is also included.

Line Monitor showing a trace of an X.25 line

This very useful feature allows Network Managers and System Installers to locally or remotely analyse and rapidly diagnose problems that may occur on the X.25 lines without the need for expensive external line monitors.

The line traces can be saved and viewed later, for example in a customer support situation.

Maintenance Contract

FarSite recognises that this product is frequently used as a key component in networked systems and as such a guaranteed response to unexpected problems is required. Maintenance contracts are available for the FarLinX Mini Gateway for fast hardware swap out, firmware upgrades, priority service and rapid problem resolution.

Rear Panel View

FarLinX Mini Gateway - view of rear panel
Rear panel view showing, 12V, 1.5A power input, system reset button,
AUX port for async pad access, WAN port for the X.25 connection and a LAN connection.

Technical Specifications
XOT <-> X.25 connection routing PVCs and SVCs; SVC routing is flexible with support for wild-cards and address translation
TCP/IP <-> XOT connection routing SVCs; SVC routing is flexible with support for wild-cards and address translation
TCP <-> X.25 / XOT call routing modes Statically defined routing, Dynamically configured routing, PAD Routing, X.25 data switching
Data packetization Includes Customisable Message Header Conversion, Cisco RBP, RFC-1006 and packetisation of messages terminated by specific characters (ETX, Carriage Return etc), X.25 parity conversion
POS Protocols Optional software upgrade to support Point of Sale protocols APACS, ISO 8583, HGEPOS and CTL (Card Tech Ltd)
X.28 PAD X.28 Host PAD and X.28 PAD terminal support. PAD support is available through Telnet and the
built in async port.
Secure connections over TCP/IP IPSEC option selectable for support of authenticated and encrypted data connectivity over TCP/IP
Data packets per second Up to 400 messages per second
Maximum connections Up to 50, can be any mix of SVCs and PVCs
Logging key events Events log maintained for events such as the connections and disconnections, X.25 call failures, X.25 line down, and X.25 line up. Log auto archived daily. The most recent events are displayed in real time on a scrolling display in the Browser. Can be routed to syslog for remote logging
Line Monitor Line monitor application included for display of frames and packets on X.25 connections, can be run locally or remotely. Wireshark supported.
Configuration Securely configured by a Browser and Java applets using XML, login required. Configurations can be saved.
SNMP Alerts Configurable levels, generated for events such as X.25 line down, X.25 line up, connections established and disconnections and gateway failures (when in dual operation).
Statistics Statistics provided for line activity, line errors, protocol problem, Gateway activity. Resetable on demand.
X.25 network connectors Connections for RS232 (V.24), X.21, V.35 and, RS530 (RS422) available.
Line speeds up to 64Kbits/s; internal and external generated line clocks.
X.25 network cables are ordered separately, see the list of available cables
Types of X.25 connection X.25 network, leased (fixed) line
Types of PAD connection Async line, Telnet
X.25 feature summary Data packet size up to 4096 bytes
SVC and PVC logical connections
X.25 CCITT Compliance 1980, 84 and 88
DCE and DTE operation
Reverse charging, Closed User Groups (CUG), Network User Identification (NUI), Fast Select, Throughput Class Negotiation
Hunt groups, backup lines
Compatible with all known public and private X.25 networks
XOT Specification Complies with RFC 1613 – X.25 over TCP (XOT)
LAN 10/100 BaseT LAN port, RJ45.
TCP/IP IP and IPv6 supported
Approvals CE: EN55022:2006+A1:2007, EN55024:1998+A1:2001+A2:2003, EN61000-3-2:2006,
EN61000-3-3:1995+A1:2001:A2:2005. FCC part 15. UL. Safety: EN 60950-1: 2006. RoHS2 compliant.
Power Requirements 100vac to 240vac, 50/60 Hz, 6 Watts.
Physical Solid state design, all metal case, software selectable power down. Reset to factory defaults switch.
Dimensions: metric – 170(W) x 158(D) x 34(H) mm, imperial – 6.7”(W) x 6.2”(D) x 1.4″(H)
Weight: 0.57 kg (1.25 lbs).
Operating Temperature range: 5 to 40°C (41 to 104°F), Humidity: 20% to 95% RH (non-condensing)
Storage Temperature range: 0 to 70°C (32 to 158°F), Humidity: 5% to 95% RH (non-condensing)
Warranty period 2 years


Order Information

Product Name


Product Code
FarLinX Mini Gateway 1 X.25 line Gateway supporting X.25 to XOT and X.25 to TCP/IP up to 50 sessions. Compact solid state appliance. Includes 1 async PAD port. Clock generation. This Gateway is available with or without IPSEC encryption over TCP/IP.

Product codes ending in N indicate no encryption, those ending in E indicate with encryption. The Gateway when supplied with encryption requires an export license for some countries.

POS Gateway Upgrade POS Software upgrade to the FarLinX Mini Gateway. Enhances the Gateway with Point Of Sale protocol handling including
Cable Options

RS232/RS530 DTE (V.24, X.21bis/ EIA530) cable with DB25M connector, suitable for Gateway generated or external clock generation, 1.5 metres FS6006
GCX1-DTE X.21 DTE (V.11) cable with DB15M connector, suitable for Gateway
generated or external clock generation, 1.5 metres

V.35 DTE cable with standard M34M connector, suitable for
Gateway generated or external clock generation, 1.5 metres
GCR1-DCE RS232/RS530 DCE (V.24, X.21bis/ EIA530) cable with DB25F connector, suitable for Gateway generated or external clock generation, 1.5 metres FS6001

X.21 DCE (V.11) cable with DB15F connector, suitable for
Gateway generated or external clock generation, 1.5 metres

V.35 DCE cable with standard M34F connector (V.35F), suitable for Gateway generated or external clock generation, 1.5 metres FS6003
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