Interface and signalling procedures for operation with the most commonly used radio stations
Application-specific configurations
Touch-Panel interface
Universal Radio Interface
Description
The widespread implementation of mobile radio networks as an instrument of rational works management for users requires, in ever increasing measure, operational equipment meeting the special requirements of flexibility and operating comfort. In this connection, a microprocessor-controlled operating station has been developed that fulfils these demanding requirements.
Modern frequency synthesizers and microprocessor technology permit the development and manufacture of complex radios having high levels of economical usability. Trunking techniques allow covering a wide geographical area. Analogue and digital selective call and data transmission raise efficiency and quality. Access through dial switching on telephone networks (PABX, PSTN) is today’s state of the art. Modern operational centres have to fulfil the prerequisites in order to support such performance characteristics of modern modems. Growing operational centres such as those of police, fire departments or ambulance services, which, with time, are unconventionally upgraded, become complex, inflexible and increasingly undependable. Increasing numbers of mobile subscribers further lower the efficiency of the entire system with the result that modern radio requirements can no longer be justified.
Applications
The FBT-126 Radio Operator Console serves as a system component for command control positions of a works management system having small, medium or large capacities. Applications include police and security organisations as well as fire departments or other users for remote control of stationary radio installations. Because of its diverse possibilities for remote control, the stationary station can be positioned immediately adjacent to the antenna location to reduce power losses.
The application of a digital console system such as the FBT-126, equipped with universal hardware and standardised software elements, makes it easy to react quickly and economically to the varying requirements of the user. Implementation of efficient microprocessors allows configuring user interfaces in compliance with customer’s needs. Digital signal processors (DSP) allow all possible types of signal processing necessary to carry out diverse standardised analogue or digital signalisation procedures including those associated with data transmission.
The FBT-126 is not conceived for a specific application. It rather represents the universal answer to the requirements of a modern operator’s station. The result of the development has yielded a digital radio operator’s station that is flexible, universal and expandable. Flexibility was achieved through the extensive configurability of the user interface. Special call formats and channel links are essential components as well. Because of its universal interface, the FBT System can be connected to all common current radios of the various manufacturers. This avoids dependence on radio manufacturers. The FBT System is expandable in accordance with growing operational requirements. The number of physical channels and those of the radio work stations can be essentially arbitrarily extended through cascading. An interface also allows remote control via a subordinate operational computer. Or as back-up in computer controlled Command & Control Systems.
Options
Various options allow adaptation to existing radios and to diverse task designations, for example:
Voice ciphering, having a high depth of security, can be built in for those applications involving security.
Data interfaces allow integration into a superposed management system.
Maritime Applications. Addition of an external accessory makes the operating part suitable for use in international coastal radio installations as well. Functionality then corresponds to the IMO guidelines for the Global Maritime Distress and Safety System (GMDSS) for emergency call handling and automatic switching of ship radio transmissions to the public telephone network.
A special modem allows operation in analogue and digital synchronous carrier system networks.
Design
In accordance with system requirements and following discussions with the user, components belonging to the FBT System, such as the FBT-126 Radio Operator Console, the FBT-MA12.12 Audio Matrix and other units are factory configured before delivery. The links between the individual functional units are via plug connectors. Insofar as possible, all connecting cables are supplied at the required length and completely wired. This allows complete testing at the factory. In most cases, additional on-site wiring effort is then no longer necessary. To a great extent these measures protect against unpleasant surprises within the scope of the commissioning work. Commissioning time is thus reduced considerably. Local businesses or representatives are then placed in the position of being able to carry out installation and commissioning to a great extent themselves.
Most of the functional units are housed in 19”/3U chassis, allowing them to be built into existing rack systems. Various power supplies are available for powering the system.
Characteristics
As a result of the consequent implementation of microprocessors in conjunction with a powerful signal processor (DSP) of the latest generation, broad accommodation to the various capacity requirements of the network operator is economically achieved. The following characteristics clearly illustrate this:
1. Number of channels
12 physical simplex or duplex channels. Expandable.
2. Circuit switching
All channels can be linked to a PBX or to intercom stations.
3. Intercom
Voice communication is possible between individual operator stations.
4. Signalling
Analogue:
SSFC, DTMF, CTCSS or others.
Digital:
FSK/PSK/QAM, configurable according to
BIIS, BOS, MPT-1327 or others.
POCSAG Encoder.
5. Supervisory control
Coded instructions or special commands to mobile subscribers for remote control purposes.
6. Remote control
Channel and operation mode control via digital transmission on 2/4-wire lines (inband or outband signalling).
7. Control tones
Control tones of e.g., 304/3300 Hz are generated for remote keying of remote radio stations (ASCOM, BOSCH, MOTOROLA TRC) or FSK telegrams.
8. FMS Radio Message System
Interface for superposed Radio Message System within the scope of an operational computer concept.
9. Ciphering
End-to-end voice ciphering of a high security level for use by authorities and other on-demand users. Suitable for 12.5 kHz narrowband networks.
10. Synchronous carrier system
A special modem is available for precise synchronisation of all basis stations. The modem ensures precise network-wide carrier synchronisation and is equally suitable for analogue and digital network structures.
11. Data modem
(Version B) Data modem function for link control and data transmission; configurable.
12. Voting
(Version B) RX Voting, 3 to 8 channels
13. Control sequences
Configurable control sequences are generated for the remote control of remote radio stations:
SSFC, DTMF sequences,FSK/PSK/QAM telegrams
Specific tone sequences according to frequency, time and level as well as combinations of several signalling methods.
14. Interface 1
Universal interface to RS-485.
15. Interface 2, 3
Host interface to RS-232.
16. Interface 4
Universal parallel interface to FBT-MA12.12 voice matrix. Connection to 12 physical channels and to 6 (12) radio operator consoles. Through its universal interface, the voice matrix allows connecting to all current stationary radio stations, local or remote, of different manufacturers.
17. System time
Real time clock for local display of time and date. Automatic summer and winter time switchover (Version B)
18. Audio equipment
Local microphone and loudspeaker or by switchover to headset and foot switch.
19. System test, BITE
Internal test circuitry for periodically checking own function.
20. Display
Large, bright alphanumeric display with 32 characters. LED-matrix 5x7, 12 mm. Application-specific configurable. Connection for external Touch-Panel Display.
Functional Units
Base Station. The FBT System is transparent to the user. The radios of any commercially-available manufacturer can be connected. Standardised interfaces, in the simplest form, 4-wire with E/M signalisation (keying, squelch), simplify the connection. A 2-wire interface for AC control is available as an alternative. The channels of the basis station can be remotely controlled using tone signalisation or FSK telegrams.
Audio Matrix. The key task of the nonblocking Audio Matrix is to connect, at any arbitrary time, peripheral equipment, radio equipment or a data terminal, PABX or intercom, via any arbitrary basis station to any arbitrary mobile user. The connection can be used to transmit voice, data or analogue or digital signals. All radio workstations have equality of access. Even if a radio channel is already occupied by another workstation, an arbitrary number of workstations can nevertheless switch to this channel without influencing one another. In addition, two-way communication among the various workstations is possible. Using the Audio Matrix, channel links can also be implemented for certain call combinations during a fire, the fire department, ambulance services and police should be simultaneously that can be entered in the FBT operating part. This could be the case, for example, if contacted on different radio channels using voice and pagers.
Calls from mobile users to the control centre are forwarded to all operating locations via the Audio Matrix. The operator first accepting the call is responsible for further handling until the communication has ended. Using the operating part, an operator can forward a call to or from the main operating centre to the telephone level location or to an intercom station. An universal interface is available for this purpose.
If a malfunction occurs in an individual functional module, the Audio Matrix is so conceived that overall functions remain unaffected. In case of faults, operation can be continued by other workstations. If a channel module fails, operation over the remaining channels is possible from all workstations. This technically comprehensive concept raises system availability considerably, a must for radio systems associated with security-related responsibilities.
If additional channels or workstations become necessary, the Audio Matrix can be essentially arbitrarily extended by cascading.
Interfaces. A 2-wire AF interface is available for voice recordings. This interface carries the receive and transmit signals on a per-channel basis including all signalisation. In the basic configuration, six universal interfaces are available for transmissions from radio users at telephone-level locations or intercom stations. These communicate the audio signals and signalisation to and from PABX/intercoms.
Two serial RS-232 and an RS-485 interface are available for integrating into superposed computer-controlled operational centre systems. This allows direct access to the audio matrix and operating parts. Both interfaces can be configured within wide limits to match format and function of specific requirements.
A connection is available to an external monitoring device which allows monitoring all channels. This is similar to the interface for voice recording. Such a device can be assigned to any individual workstation.
Radio Operating Part. A very essential component of the FBT System is the operating part for the radio workstation. Within the scope of the concept of distributed intelligence, each operating part is provided with its own processor. This makes each operating part autonomous, with equality of access. There is no dependence on other superposed control equipment.
Radio Operating Part
The voice equipment includes a swanneck microphone and a built-in loudspeaker. It has a connection with switchover allowing a headset to be used instead of the built-in microphone and loudspeaker. Transmission keying is controllable by a key or using a foot switch.
The user interface consists of a large, bright LED display having 32 alphanumerical characters. These can be configured in accordance with individual requirements. Input is via two keyboards for channel selection and selective call number entry. Several special functions can be assigned to keys supplied for this purpose.
The key tasks of the FBT-126 Operating Part consist essentially of: providing AF for the user and modulation for the basis station, targeting channel selection and making the connection with the mobile user following entry of the selective call number. In the basic configuration, up to 12 basis stations can be connected. If necessary, an additional channel selection via FSK telegrams can be implemented per basis station. Input of the selective call is via abbreviated dialling keys or by entering variables associated with the mobile number. Special calls, such as e.g., background interrogations, take place via relevantly configured function keys.
Several selective call procedures can be used, such as 5-tone sequences or special FSK telegrams. Instead of 4-wire lines, remote control of remotely-located basis stations is also possible using control tones of selectable frequency and amplitude on 2-wire lines. In addition, by using relevant signalisation, data terminal equipment (modems) can provide remote control of external equipment and functions. Calls from mobile users to the central are displayed on the local alphanumeric display. Status and emergency calls are handled separately. The digital signal processing procedures allow increased call and false call security even under poor channel conditions.
An existing connection to a mobile user can be connected to a PABX or intercom user using a transmission command from the operating part. The display indicates which channel is connected to which PABX/IC user. Interruption of such a connection is possible anytime, not only by those communicating, but also by the operating part.
For securing voice communications, each operating part can also be equipped with its own SEU-8200 Voice Ciphering Module. In this case centrally located ciphering is purposely avoided for reasons of redundancy. This allows stable end-toend ciphering, ensuring synchronisation even along several relay stations.
The FBT-126 Radio Operating Part has several interfaces, one of which is used to control the Audio Matrix and its feedback signalisation. Another serial interface is used for data exchange and co-ordination among individual radio workstations. An additional RS-232 interface can be used for general applications, for example for connecting a printer or PC. It can also be used as a gateway port for connecting, if necessary, a superposed computer control system.
Summary
The FBT System fulfils today’s requirements for modern radio-centre equipment. Through consistent application of the latest technology, in conjunction with modular structured hardware and software, it becomes possible to quickly react to all conceivable requirements. Analogue and data interfaces raise efficiency and allow extension through standard or customerspecific peripherals. Signal processors allow adapting to all possible types of analogue and digital signalisation formats. Operating security is characterised, among other things, by the absence within the FBT System of central control equipment that, in case of malfunction, could take the entire system out of service. Owing to numerous expansion possibilities, distributed intelligence and careful manufacturing procedures, a high level of availability is achieved. Because of this, the FBT System offers a meaningful investment offering a high level of serviceability for years to come.
