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Intelligence at service of aviation

AFTN message switching center

AFTN message switching center is intended for work in a ground network of aeronautical data transmission and cable communication

Purpose and structure

Automatic Message Switching Center «Monitor» (hereinafter CKS) is intended to work in aeronautic data transfer and in telegraphic communication network of civil aviation.

CKS provides automatic message receipt, analysis and processing, routing, registration, archiving and transfer to users via 4…256 telegraph channels, data links and network channels formatting ICAO-AFTN.

CKS provides control over communicating channels condition, queues on transfer, support of technological unity of  aeronautic data transfer and in telegraphic communication network and guaranteed message delivery to users in constant clock round duration.

CKS is a system with back-up, that contains computing, baseband, network and peripheral equipment and software.

Structurally CKS «Monitor» is located in standard 19-incher (19”) on 42U (or 47U) rack cabinets.

CKS administrator and operator workspaces are realized on the base of a standard desktop PC, and are linked with a server rack cabinet by local network.


CKS «Monitor» structural layout


CKS version with capacity up to 16 telegraph channels


Main technical characteristics

Total amount of communicating supported channels is up to 1000.

Total amount of telegraph channels and Data Transfer channels connected (is determined in amount and type of RS channel multiplexors connected) is from 1 to 128.

Remote CKS users, that are part of aeronautic data transfer and in telegraphic communication network, may be any AFTN communication systems, telegraph devices and subscribers, connected to modem computer network (INTRANET / INTERNET).

As autonomous (internal) users both telegraph devices and computer automatic workstations (WS) with functional software of the corresponding services subsystems (subsystems "NOTAM", "TWR", "PDS", "METEO" etc., connected to CKS by telegraph channels or by local/ in-house computer network can be used.

System administrator and operator servicing CKS work on CKS console or on distant stations. User interface of administrator or operator stations is built in the unitary graphical stile in accordance with modern ergonomics requirements and provides access to the system resources regarding each user’s rights.

As CKS communications channels the following can be used:

·      Telegraph or physical communications channels.

·      Telegraph dial-up modem communications channels using TCP/IP (Intranet / Internet is also possible).

·      Telephone dedicated modem communications channel using TCP/IP.

·      Communications data transfer channels using X.25, Frame Relay etc.

·      Local area network data link  using TCP/IP or NFS.


Informational or service messages formats are ICAO-AFTN with national extension

Telegraph messages codes:

·      A five-element MTK-2 code (Latin and Cyrillic);

·      A seven-element -5 code (Latin and Cyrillic).

CKS performs transformation of code MTK-2 into code MTK-5 and vice versa to interface communication channels with MTK-2 code and communication channels with MTK-5 code.

Exchange speeds by communication channels, supported by CKS (are set individually for each channel) are the following:

50 Baud;              75 Baud;     100 Baud;         150 Baud;    200 Baud;    300 Baud;

600 Baud;        1200 Baud;   1800 Baud;       2400 Baud;  4800 Baud;  9600 Baud;

19200 Baud;  38400 Baud;  56800 Baud;  115200 Baud.

Exchange speeds by network channels and by data transfer channels are determined by speed characteristics of the corresponding networks.

 Communication channels operating modes:

·         duplex, semi duplex, simplex;

·         round-the-clock, according to the schedule;

·         communication sessions (users that don’t have persistent connection can connect with dial-in access via dial-up telephone channels);

CKS provides a round-the-clock operating mode with guaranteed time before failures not less than 10000 hours.

CKS equipment service life is 10 years.

Operation condition

CKS hardware provides an uninterrupted round-the clock operating mode.

Hardware power voltage is :  220V ± 10 %

CKS power supply can be achieved by uninterruptible power supply (UPS type) if there is no a guaranteed power supply network (in accordance with the documentation to the UPS chosen).

Operating climatic service conditions:

  • surrounding temperature from +10 up to +35°;
  • relative humidity from 40 up to 80% at a temperature of +25°;
  • atmospheric pressure from 84 up to 107 kilopascal (from 630 up to 800 Mmhg).

“Monitor Soft” Ltd.  is ready to provide AFTN message switching center itself and additional information about it for test operation to all interested recipients of air navigation information (such as airlines, airports and regional governments).