Trunking communication in the security business.
In their work, employees of private security companies, bank collection services, and transport organizations actively use various types of mobile radio communication: paging, radio (conventional), radiotelephone, cellular, and trunking.
The first mobile radio communication systems were organized in the USA in the early 1930s. Police cars were equipped with conventional (conventional) radio stations.
They were single-channel and allowed maintaining radio communication between dozens of subscribers.
One of the disadvantages of such communication is the fact that the number of subscribers is not enough. limited number of users who could work on air at the same time.
During the Second World War, the first multi-channel systems appeared. However, they lacked any means of optimizing the use of channels. Each group of subscribers was assigned a permanent frequency channel.
The transition from one group to another was carried out by simply switching the frequency. New groups of subscribers were connected by introducing new frequency channels.
This partially solved the problem of limiting the number of users.
However, subscribers often had to «jump» from channel to channel in search of a less busy one.
At the end of the seventies, the first pseudo-trunking communication systems appeared.
The main difference from multi-channel conventional radio communication is the optimal use of channels.
When organizing a communication session, all frequency channels are scanned and a free one is determined. Data is exchanged over it.
These include the following systems: SrnartTrunk, ETrunk, ArcNet and others.
In the early eighties, the first «analog» trunking systems began to appear. Unlike pseudo-trunking systems, they had a dedicated channel for transmitting service information. This significantly accelerated the process of establishing communication between two subscribers.
The most popular in Russia are: MRT 1327, EDACS, SmartZone, SmartNet and others.
And in the nineties, trunking communications gradually began to move to digital technologies for transmitting voice signals. This made it possible to ensure the necessary level of confidentiality of communications and provide a host of additional services to users. These systems have only one drawback — the price. The cost of equipment for «analog» networks is 2-3 times lower than for «digital».
Despite their widespread use in the West, «digital» systems will probably not be able to take a leading position in the Russian market in the coming years. In the coming years, they will be used primarily in the field of corporate (departmental) communication networks. For example, in transport, in the energy sector, and possibly in law enforcement agencies.
The peak of popularity of pseudo-tracking systems in Russia was the mid-nineties. At that time, many considered them as an alternative (cheaper) to cellular networks.
Security and collection services of numerous commercial banks willingly purchased equipment to work in these systems.
After the financial crisis of August 1998, many consumers working in the security sector were forced to either abandon this type of communication or continue to use morally and physically obsolete equipment.
The first commercial pseudo-trunking network ETrunk began operating in Russia in March 1993 in the 160 MHz range. It was organized by AOZT «Radio Leasing».
In 1996, the State Committee for Radio Frequencies of the Russian Federation decided to allocate the 470 — 486 MHz range in Moscow for the organization of commercial trunking public radio networks.
More than 50 organizations participated in the tender, five of which won the competition.
As a result, one of the tender winners — ZAO «Radio Leasing Ltd.» — managed to organize one of the largest commercial trunking networks TransLink in the Moscow region.
Today, the border of the network service area is up to 45 km from the Moscow Ring Road.
Russian and Western experts who have been working in the field of personal and corporate security for many years name at least ten advantages of trunking systems over other types of mobile communications.
Protection from wiretapping.
Messages transmitted via paging, radio and cellular communication channels are easily intercepted using publicly available equipment.
Trunking communication provides protection at two levels.
The first is the technology of organizing a communication session itself. The message is transmitted via one of the set of channels that is free at that moment.
This complicates the interception process — you either need to control the broadband frequency range, or have time to switch to the desired channel.
The second level is the use of special equipment to close the communication channel itself. For example, scramblers.
Instant connection.
A person dials a subscriber's number on the keyboard of his radio station, and after 0.1 — 0.3 seconds he already hears the voice of the interlocutor.
When calling from a «mobile phone», the wait can last several tens of seconds.
Minimum probability of a busy line (channel).
In trunking communication, the probability of such a situation is 0.5%.
It is clear that in cellular systems this figure is much higher.
It goes without saying about radiotelephones.
Conventional radio communication is almost completely free of this drawback.
You will not hear short beeps.
But the probability of establishing a connection depends on the power of your radio station.
Compliance with the MILITARY standard.
Speed bump mode..
If the radio station is in a horizontal position for more than five seconds, it will start transmitting an alarm signal.
Possibility of «group» and «individual» calls.
What is good about conventional radio communication?
The ability to simultaneously talk to several subscribers.
This principle can be called «Attention all posts!»
What is bad about it?
If someone wants to send a message to one subscriber, he is forced to disturb the entire group.
Each guard has to constantly keep his radio in «receive» mode or nervously react to each call.
Even if it was not intended for him, but for someone else.
Cellular communication has a different problem.
Individual communication is well organized, but it is extremely difficult to transmit a group message. Trunking communication provides for «group» and «individual» communication.
Priority system.
All messages transmitted over mobile radio channels have different priorities. Some must be transmitted immediately.
For example, a signal about an armed attack.
And others can wait a few minutes. A subscriber or a message with a higher priority can «download» or interrupt a lower dialogue.
Simplicity of organizing a local communication system.
Often, it is necessary to equip a separate object with radio. For example, a shopping center, an office building, an airport, etc.
There are three options.
You can contact a mobile operator.
Then each guard will need to be provided with a «mobile phone».
However, there is a high probability that the area where the guarded object is located is not serviced by mobile operators or the costs of using «mobile» communications are too high.
Another option is to give each security guard a conventional radio station. The disadvantages of each option were described in detail above. Therefore, the best option is to create a local trunking network.
An alternative to conventional radio communication systems.
The widespread enthusiasm for amateur and semi-professional communications operating in the civilian range (27 MHz) has led to the fact that the communication range in Moscow has decreased from 1 km to 400 — 500 m.
All this is superimposed on the peak of solar activity of 1998 — 2003, when, due to the peculiarities of communication at 27 MHz, signals from powerful stationary amateur radio stations travel 1000 km or more and «clogg[e]» all signals from amateur low-power stations.
The ability to transmit digital data over a radio channel.
• from navigation systems based on GPS receivers;
• from barcode scanners;
• from devices for reading information from plastic cards;
• digital commands;
• telemetry information (remote monitoring and control of technological processes);
• small volumes of text and other information.
Possibility of using it in radio security and life support systems of the protected facility.
Messages from various sensors can be transmitted via trunking communication channels: alarm buttons; motion detectors; security and fire alarm sensors; humidity sensors; temperature sensors and other devices.
Trunking communication systems are maximally adapted to the specific working conditions of not only security personnel, operational units of law enforcement agencies, rescuers, firefighters and all those who are forced to constantly work in conditions of constant risk, but also those who work in a mode of constant movement.
For example, a cargo delivery service, repairmen or construction organizations.
Operational radio communication in general and trunking communication in particular is the organization of any process in a fast and optimal way.