Technical Spec´s X.25 PCMCIA *

© Farsite Communication Ltd. • 2012

The FarSync X25 M-Series PCMCIA adapters provide high performance X.25 communications for Laptops and PCs using PC Cards.

Product Overview

The FarSync X.25 M1P v2 adapter has been developed to provide high performance X.25 connectivity for Windows XP, Vista, Server 2003 and Server 2008. The 1 port PCMCIA card can utilise lines up to 512 Kbits/s with support for RS232C, X.21, RS530 (RS422) and V.35 network interfaces.

The X.25 software has a host of features including ISO Transport (classes 0 to 3), IP over X.25, support for OpenFT FTAM, a WinSock2 compliant Sockets API, a Java API, a COM Port API, a low level NCB 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.

The FarSync X25 cards and software are well proven and very reliable making them ideal for non stop applications.

When used in conjunction with a low profile PCI to PCMCIA adapter the FarSync X25 M1P v2 card provides an economic X.25 solution for low profile servers with PCI slots.

A comprehensive Developers Toolkit is included with each product together with a GUI multi-port Line Monitor and a Line Statistics application.

Typical Applications

The FarSync X25 M-Series PCMCIA cards are suitable for connection to all types of X.25 networks, X.25 over the ISDN D channel, Dialup X.25 and leased lines. Example 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
        • FTAM access
        • Billing and Mediation
        • X.25 connections to Laptops including military Laptops
        • X.25 solution for low profile PCI Servers (in conjunction with a low profile PCI to PCMCIA adapter)

The card is compatible with all public X.25 networks, including: Datex-P, BT X.25 Direct, Eirpac, Austpac, Transpac, Iberpac and Itapac and many more.

Application Development

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.

Sockets API - X.25

The Sockets API is extremely popular as a simple, easy to use API to access TCP/IP communications networks. The Sockets support for the FarSync X25 M1P retains this ease of use and also allows the special features of X.25 and ISO Transport classes 0 to 3 to be accessed.

The Sockets interface is WinSock2 compliant, it supports standard AF_ISO / ISOPROTO_X25 sockets used by a number of applications, such as MS-Exchange. It also supports an alternative address family, AF_X25, to allow easy porting of applications between Windows and Linux.

The FarSync Sockets API is compatible with the Microsoft defined X.25 Sockets API. Applications written to use the Microsoft X.25 Sockets API will work with the FarSync product.

Applications developed in most programming languages including Visual Basic, Delphi, C++ and .NET applications can use the Sockets API to the FarSync X25 M1Pv2.

Java API - X.25

The Java API allows applications written in Core Java Software (J2SE) and Enterprise Java Software (J2EE) easy access to the functions and features of X.25 offered by the FarSync X25 M1P card. Full documentation and sample applications are provided.

COM Port API - X.25

The COM Port API provides a very quick and easy to use interface to X.25. Each X.25 session is represented by a COM Port controlled by AT commands. The COM Port API is particularly suitable for applications developed in Visual Basic and similar languages or for those who would prefer to address the card as if it were a modem type device. Full documentation and a sample application is provided.

NCB API - X.25 and ISO Transport

A legacy API is supplied to maintain compliance with older X.25 cards, access to ISO Transport and X.25 is provided.

Developers Toolkit

The X.25 Developers Toolkit is included with the FarSync X25 products and features:

        • Documented working sample programs for Linux and Windows, including in C, Java, Visual Basic and Delphi. Source code from these samples can be used to fast-track your development process
        • Comprehensive set of API manuals with function call definitions and helpful advice on the best way to utilise the various interfaces
        • Free email and telephone assistance to the application developer using the APIs

TCP/IP over X.25

The IP over X.25 support is included as part of the FarSync X25 M1P product, it is fully integrated into Windows

Configuration is performed using standard network configuration menus.

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.

Card Performance

The intelligent FarSync M-Series card offers high performance in a small package. The software supports a full set of X.25 features whilst still providing high data packet throughput.

        • Up to 254 simultaneous virtual connections
        • up to 500 pps (data packets per second)
        • Line speeds up to 512 Kbits/s
        • X.21 (V.11), V.35, EIA-530 (RS530, RS422) and RS232C (V.24 / X.21bis) network interfaces

Fast Installation and Configuration

The card features 'Plug and Play' support for Windows XP, Vista, Server 2003 and Server 2008. Fast installation and easy configuration are a feature of the product.

There is context sensitive help and an on-line manual. 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 should it be required .

Line Monitor and Network Statistics Utilities

The product includes a multi-port line monitor, an invaluable tool when testing new applications and commissioning new systems. Line traces can be displayed in real time, recorded and reviewed with full protocol decoding, comments can even be inserted in the trace to assist later analysis.

A connection status and statistics utility is also provided. Its functions include the display of the channel connection status and statistics of user data, packet and frame types passed over the X.25 lines.


The X.25 software, utilities, IP over X.25 support and the development tool kit are all included on the CD-ROM supplied with the FarSync communications adapter. Cables are ordered separately.

Technical Specifications - Software Features

Operating Systems supported

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

Line Monitor

Yes, multi port, decodes and displays frame, packet and data levels. Traces can be logged to file and reviewed. Insert text comment facility.

X.25 Software Features

Data Packets per Second

> 500 pps throughput

X.25 CCITT Compliance

1980, 84 & 88

DTE/DCE Operation

Both & Auto Select

Maximum SVCs (all types)

254, any mix of bothway, incoming & outgoing

Maximum PVCs


Logical Channel Numbers (LCN)

From 1 to all 4096 LCNs can be specified. Allows incoming calls to be accepted on any channel

Data Packet size range

16 to 4096 bytes

Reverse Charging option


Closed User Group (CUG)   option


Network User Identifier (NUI)


Fast Select


Packet & Window size negotiation


Throughput class negotiation


Extended sequence numbering (128)


IP over X.25

Included, supports RFCs   1356, 1598 & 1662

Accessible via API

Yes, 4 APIs available (Sockets API, Java, COM port, NCB)

ISO Transport Features

Standard supported

ISO 8073 (connection   oriented)

Classes supported

Classes 0, 1, 2 and 3

Negotiation between classes


Transport connections


Accessible via API

Yes, Sockets API   (Winsock2)

Development Toolkit

X.25 APIs on Windows

Sockets API, easy to use, provides access to the   majority of X.25 features, recommended for most developments.
Java API, specially developed for Java applications (J2SE, J2EE), quick and   easy to use. 
COM Port API, quick and simple to use suitable for many applications particularly those based on Visual Basic and similar languages.
HDLC API provides a programming interface into LAPB (X.25 Layer 2). an alternative API is provided to raw HDLC frames, with the API just providing the CRC generation and the framing.
NCB API A legacy API to maintain compliance with older products only.

ISO Transport API on   Windows

Sockets API, providing access to all the features of   the ISO Transport support. Can operate simultaneously with access to the   X.25.
NCB based API, legacy API providing access to all the features of the ISO Transport support. Can operate simultaneously with access to the X.25.

API reference manuals

X.25 Sockets API manuals, Java API documentation, ISO Transport API   manuals, Com Port API Manual, NCB API manuals, HDLC API Manuals

Sample programs

Included, large number of example applications are available for driving all the various APIs. Includes samples for SVC and PVC operation

Technical Specifications - General and Hardware Features

Product Name

FarSync X25 M1P v2

Product code



Free 5 year warranty

Hardware Features

Card type

PCMCIA type II PC Card

PC card cable connector

FCI rocard

Max port count

1 port

Multiple cards in a PC

yes, 2 or more

Network Interfaces

RS232C (V.24) - 25 pin male D type,
X.21 (V.11/ RS422) - 15 pin male D type,
V.35 - MRAC-34 male 'brick' type,
EIA-530 (RS530) - 25 pin male D type,
RS449 can also be supported

Link speed range

RS232C: up to 128 Kbits/s
X21, V35, EIA-530: up to 512 Kbits/s

ESD protection

Yes, Littelfuse high speed ESD and over-voltage protection


EN55022 class B, CE


468,787 hours. Bellcore Method 1 Case 3, 40 deg.C ambient, 15 deg.C case temperature rise above ambient

Power requirements

< 150 mA @ +5v
< 0.75 watts

Internal/External Line Clocking

Both external and card generated. The card generated clock range is   from 9,600 baud to 512 Kbits/s on RS232C and X.21 type connections only. No   special cables are required to use card generated clocks.

* All specifications are subject to change