General Description


The communication system of railways is one of the oldest and probably the most difficult departmental communication system. In recent years, active modernization of railway networks began. Digital PABX are installed, thousands of miles of fiber-optic communication lines are laid, new technologies that open up new opportunities for the management of passenger and cargo transportation are implemented.


Group of companies "Informtekhnika" offers equipment developed on the basis of the latest telecom technologies and at the same time taking into account the specific requirements of the communication system of railways. Hundreds of "MiniCom DX-5OO.ZHT" stations are successfully operated on Oktyabr, Kaliningrad, Moscow, Gorky, Northern, North-Caucasian, Kuibyshev, Sverdlovsk, the Far East, Sakhalin, Yamal railways, railways of Yakutia, Uzbekistan, Ukraine, Kazakhstan, Afghanistan.


Special solution for communication networks of railways


Switching system "MiniCom DX-500.ZHT" is a special version of digital PABX "MiniCom DX-500" mass-produced by "Informtekhnika". Telecommunications equipment "MiniCom DX-500.ZHT" is designed specifically for use in the communication networks of railways in accordance with the requirements of the "Terms of Reference for the development of digital PABX system for railway transport", ATS-C code, 1994, "Terms of Reference for the development of equipment of operative and technological communication for Russian railways", OTS-C code, edition 2/1998, developed by VNIIAS RW and approved by the Department of signaling, communications and computing of the Ministry of communication lines of the Russian Federation, as well as documents "System of Operative and Technological wired communication for Russian Railways. Principal technical and operational requirements", edition 2, VNIIAS RW, 1997, OST 32.145-2000, "System of operative and technological communication for Russian Railways", OST 32.180-2001, "System of timing network synchronization for Russian railways" and the concept of modernization of communication system of Russian Railways.


In close collaboration with engineers of VNIIAS (VNIIUP) RW the developers of "Informtekhnika" achieved full technical compliance of telecommunications system "MiniCom DX-500.ZHT" with requirements of the Department of Communications and Computer Engineering of JSC "Russian Railways".


Telecommunications system "MiniCom DX-500.ZHT" was created as a single digital platform for networks of common technological and operational and technological communication, meetings communications of railways.


The developers paid particular attention to:


-         Ensuring continuity of equipment, compatibility with existing analog channels and equipment, the possibility of a smooth, gradual modernization of networks;


-         Preservation of the existing network algorithms and dispatching facilities in transition of the systems on digital channels and lines of communication;


-         Unification of the hardware switching and terminal equipment of OTC and CTC networks significantly improving its redundancy and maintainability, as well as allowing to combine the functions of these systems into a single product;


-         Provision of enhanced services of digital network with integration of services to subscribers, primarily controllers, including the transfer of video and IP-telephony, while preserving the existing management principles;


-         Increasing the reliability and quality of communication.


Scope of application


Initially "MiniCom DX-500" was designed to work on communication networks of various departments. It can be applied:


·         to build communication networks;

·         to connect a departmental network to communications networks of other agencies;

·         to access a common network;

·         to work in integrated services digital networks (ISDN);

·         In sub-systems of manual service operators;

·         In control centers;

·         In data centers and passengers service centers;

·         As meetings communication system;

·         to create a system of DECT micro-communication;

·         to interface with trunking and satellite communications systems;

·         for multiplexing and transmitting up to 4 (to 8) digital E1 flows via 1 (2) optical fibers, and a semi-permanent switching of individual MDC and data transmission.


Architecture of "MiniCom DX-500.ZHT" system allows to use it in digital networks of common technological, operative and technological communication, meeting communication system for railways of Russia, CIS countries and Baltic countries. The station may operate in both digital and analog environment, which makes its use the most effective in the evolutionary development of railway communication networks - from fully analog to fully digital. The station can perform the functions of automatic switching node (ASN) with any kind of alarm for each trunk.


Thanks to its flexible structure "MiniCom DX-500.ZHT" can be used as a local, departmental, main and road. Herewith, in OTC and CTC networks it can function as a terminal, transit or transit-terminal station. In a hierarchical series "MiniCom DX-500.ZHT" is regarded as administrative, executive and administrative, executive wired communication station and train radio communication station, being a switch of operative and technological wired communication. On the basis of "MiniCom DX-500.ZHT" the dispatch communication of new vertical of transportation management can be organized using dial-up, group and direct channels.


Types of communication


In accordance with the requirements of the Department of Communications and Computer Engineering of JSC "Russian Railways", switching system "MiniCom DX-500.ZHT" provides the following types of rail communication:


1. Managing road communication;

2. Departmental wired communication;

3. Meetings communication:

    3.1. Station wired communication;

    3.2. Managing station communication;

4. Park;

5. Waysides;

6. Data transmission of telemechanics and telesignaling;

7. Departmental wired communications:

     7.1. TrDC - train dispatching;

     7.2. TRC - train radio;

     7.3. PDC – power dispatching;

     7.4. LPC - line-path;

     7.5. SSC – station by station;

     7.6. SDC - service dispatching communication of CB and communication electromechanics;

     7.7. CDC - car dispatching;

     7.8. ShDS - shunting dispatching;

     7.9. TDC - ticket dispatching;

     7.10. TMC - transport militarized guard of the Department of Internal Affairs;

     7.11. PCC – duty officer on the protected crossing.


Equipment architecture


"MiniCom DX-500.ZHT" is a universal digital telecommutation platform. GC "Informtekhnika" implemented the latest developments to ensure the expansion of the scope of application, additional conveniences of usage, and new opportunities for management, maintenance and reliability.


"MiniCom DX-500.ZHT" is a modular system that enables simple and economical increase of capacity up to 4096 ports and 48 DTL.


Features of "MiniCom DX-500.ZHT" architecture


·         Distributed control method. Every 128 ports or four PCM lines serviced by independent CPUs with their own software.

·         Distributed switching. Each control module has its own non-blocking digital switching network.

·         Switching of speech paths within a cluster is produced without the use of centralized resources of the station.

·         Duplicated common non-blocking switching field in 1024 by 1024 ports.

·         Spatial separation of station modules for significant distances via digital paths or fiber optics.


OTC network based on "MiniCom DX-500.ZHT" is based on the principle of rings, to achieve high reliability of communication system in case of linear path failure. Equipment of executive stations of sites (up to 30 stations) is connected to the lower layer ring.


Sites are connected to managing-radio station of a road section (road UTCC) by a ring of top-level via bridge stations. Thus the top-level ring acts as a pull-up channel from the road sections to the control center. There is a function to automatically backup dispatch communications via VF channels on loss of both directions of the ring.


Using "MiniCom DX-500.ZHT" a network of long distance communications (up to 256 stations in the network) can be built, connected over E1 trunks using standard E-DSS1 protocol.


Management and administration of network


The developed of monitoring and administration system (MAS) allows to focus the control and management of geographically distributed systems, operational and technological communications on one or several operator workplaces. This provides a visual display of the current status and utilization of communication equipment, spread on tens and hundreds of kilometers.


With a convenient hierarchical display system an operator can simultaneously monitor both the state of the whole communication system and technical condition of individual sites and stations with accuracy up to a separate board and even its components.


The system provides the functions of visual and audio alert of personnel on all emergencies in communication system, logging and archiving of information on any changes in the technical condition of its components and operator’s actions.


Powerful tools for statistical analysis and visual display of the accumulated information enable to identify unstably operating components of the system and take measures to prevent failures before they can have a negative impact on providing users with reliable and uninterrupted communication.


The system is equipped with a convenient mechanism to correlate the technical and functional aspects of the communication system. The operator is provided with operational information on how a particular malfunction of hardware may occur while ensuring the communication of specific users. There is a possibility of quick search of reference information and calling any subscriber of communication system directly from the operator.


Development of the centralized maintenance system is carried out in accordance with the ideology of TMN, based on generally accepted international standards of construction of systems of this kind.


The experience of specific departments is considered. So thanks to the implemented in "MiniCom DX-500.ZHT" principle of group channels it is possible to quickly build a network of technological communication of railways on the same principles that exist today. This approach enables the operators without changing the familiar working process to get used to the new digital equipment.


Currently, the system is working in the areas of operational-technological communication of Gorky, North, Sverdlovsk, Moscow railways, where it has received high praise of operating personnel.


Mobile communications


Mobile communications for professional use is the old subject of attention of the Group of Companies. GC "Informtekhnika" has expanded its production program of component trunking mobile radio communication and offers a customer a complete solution, adding mobility and efficiency to a wide range of technological communications.


Integration with analog trunking radio systems


"MiniCom DX-500.ZHT" provides an interface of a departmental network with mobile radio systems of different analog standards (SmartTrunk-ll, MPT-1327, LTR, etc.)


Unified field of numbering of all departmental networks covers subscribers of mobile radio systems, who receive a wide range of additional services and communication over long distances. At the same time flexible programming of "MiniCom DX-500.ZHT" can eliminate one of the drawbacks of most trunking systems, which occurs when interfacing with telephony networks - the need to redial additional number of radio user (in DTMF-mode) after the outgoing to the system controller.


Digital trunking radio system


GC "Informtekhnika" developed the TETRA trunking radio communication - "MiniCom-TETRA", which has a certificate of conformity of the Ministry of Communications of Russia and has a number of competitive advantages:


1. "MiniCom-TETRA" enables to install a local gateway (E1 flow, E-DSS1 signaling) to connect to the telephone network directly from the controller of any base station without any additional hardware.


2. Controller board designed for "MiniCom-TETRA" has the following characteristics:


·         the board is implemented on the basis of "standard" wired board, "usual" for controllers that use the network of operational and technological communication on Russian Railways;

·         the board is easily programmed for a specific controller (duty officer);

·         in co-operation of PABX "MiniCom DX-500" and "MiniCom-TETRA" it is possible to enable the controller board for use with both wired and mobile users. This option allows to use existing equipment to record the conversations of a station duty officer, and requires no additional equipment and resources of the transport environment.


3. The system provides the following specialized requirements of JSC "Russian Railways":


·         call on a conditional numbers of train, locomotive, car;

·         limited group call area of ​​a mobile user according to its location;

·         limited group call area of from a fixed user;

·         dynamic forwarding of individual calls from a mobile user depending on the location.


4. Control subsystem implemented in "MiniCom-TETRA" allows to manage:


·         equipment within one module;

·         events within exchange protocol commands between a mobile user and the system.


DECT mobile radio communications


Subscriber radio and microcellular communication system "MiniCom-DECT" integrated into "MiniCom DX-500.ZHT" is a great addition to a wired connection, which increases the efficiency of production management.


"MiniCom-DECT" consists of a base station controller (BSC), base stations (BS) and mobile handsets. Base stations provide a network of radio zones throughout the territory which allow a mobile subscriber to move freely and be available for telephone calls anywhere in the enterprise. At the same time there are all PABX service capabilities, including: internal communication with all departments, access to the common network, access to the corporate network, and more.


If necessary, using "MiniCom-DECT" productive or residential properties can be telephonized, which are at the distance of 5 km (tested range -10 km) from the controller. The base station may be taken out to the telephone facility by a digital transport network, and then the distance to the controller is limited only by the length of the network.


"MiniCom-DECT" supports DECT-handsets and terminal subscriber radio units (TSRU) of all manufacturers, conforming to international GAP profile. TSRU consists of antennas and radios socket, to which an analog telephone is connected.


"MiniCom-DECT" offers a flexible scalability and can progressively extend from 50 to several thousands of subscribers.


Currently, "MiniCom-DECT" successfully operate on facilities of Russian Railways, RAO "UES", JSC "Gazprom", oil production industries and telecom operators.


System reliability


Realizing the high degree of responsibility for telecommunications equipment in the production process of railway industry, the developers of "MiniCom DX-500.ZHT" paid special attention to reliability and fault tolerance.


Distributed control


The use of own microprocessors with their own memory in each module allows to assign control of the entire system. Reliability is no longer determined by the dependence of the centralized system. With decentralized management the failure of one module has a limited impact on the overall system.


Each cluster of "MiniCom DX-500.ZHT" has its own microprocessor and a digital switching field, providing calls switching and data transfer within a single cluster.


Duplication of Systems


Resources of the station, affecting the coordinated operation of individual modules, are used centrally. Central switching device and a system of inter-module synchronization are performed using the principle of 100% redundancy.


Structure of power supply system


"MiniCom DX-500.ZHT" applies fully decentralized power supply. The station is energized by ± 48 V or 60 V from external primary power supply for two independent external inputs. Each card is supplied from independent buses. A card automatically selects a power supply bus, switching to another if one of the sources fails. Thus, the station has no internal centralized power supply.


Selection of components and production technology


"MiniCom DX-500.ZHT" is built on the basis of elemental base of the world's leading manufacturers - Analog Devices, Infineon, Hewlett Packard, Intel, etc.


To achieve a high quality and reliability of equipment the most advanced automated production of printed circuit boards with surface mount technology (SMT) of components is used.


Technical specifications


Max. capacity of a station

256,512,1024,4096 analog ports and up to 4,12,20,76 DTLs respectively

Capacity of cabinets and dimensions (D x H x W)

256 ports - 600x1100x600 mm

512 ports - 600x1820x600 mm

1024 ports – 650x2370x810 mm

Power supply


44 – 63 V

Rated input

no more than 1.2 W / port

Signal processing method

digital 64 kbps

Number of circuits (group channels)

- Up to 30 subscriber

- Up to 30 transit

- Up to 60 gateway

Types of internal ports (connected lines)

Analog 2-wire

Local - analog telephone unit

Speaker – Speaker unit

MB - MB unit


2-wire Upoe

Urban analog

2-wire urban lines

Signaling of 4-wire lines of voice frequency (VF)



• 4-wire connection to enable the analog branch of dispatching communication or train radio with 43RTS-A2-FM, PC-6, PC-46M radio stations with a frequency of 3300 Hz or with PC-6, PC-46M radio stations with frequencies of Fa, Fb ;

• 2-wire connection for consistent (KSP) or high resistance (KVP) inclusion of analog branches of dispatch communication;

• 2-wire connection to enable train radio line (PRS) with 43RTS-A2-FM, PC-6, PC-46M radio stations with DC control or PC-6, PC-46M radio stations with frequencies of Fa, Fb;

• local telephone unit with voice control (SLT);

• PGS-line of long-line with dialing of network subscriber directory number and OTC in pulse or tone mode.


Public Service Network:

• outgoing 2600 with IBSC;

• incoming SLM 2600 with pulse dialing;

• incoming SLM 2600 with IBSC.



• incoming 2600 with IBSC;

• 2600 two-way;

• 600 +750 two-way;


• 4-wire unit (2100, switch);

• outgoing 2600 with IBSC

• 2100 two-way



Signaling of PCM-lines

In urban public networks:

- Outgoing trunk / CLR trunk with pulse dialing;

- Incoming trunk with pulse dialing;

- Outgoing trunk / CLR trunk with IBSC

- Incoming trunk with IBSC;

- Incoming ICL with pulse dialing;

- Incoming ICL with IBSC.


In rural public networks:

- RCL 2ICS with pulse dialing;

- RCL 1ICS (inductive code) with pulse dialing;

- ICL 2ICS with ISDN pulse dial PRI: DSS1 (ETS300 102-1). QSIG (Q.931).

- ICL 1ICS (personal code) with pulse dialing.


Additional PCM-lines:

* PCM to connect DECT-controller (up to 512 subscribers) on the rights of its subscribers

Dedicated digital channels of data collection and transfer

Asynchronous 1200 - 19200 bit / s: V-24 (RS-232), V-11 (RS-422/485)

PABX supports data transfer speeds of up to 64 kbps