Organization of listens to large premises. IP Microphones E-Ear An interesting feature of the audiokers Stelberry

Life is not predictable, and therefore sometimes there are situations in which you need remote and secretive listening of premises, some conversations on the street or in other places. Without affecting the moral side of the question, consider the fundamental bases of the listener at a distance. What technical devices allow it to do? What are their features? What you need to know the one who decided to buy a listener at a distance? - These and other questions you will find the answers in this small review.

Conductor at a distance - theoretical side of the question

There are several ways to carry out remote and secretive listening:

• Interception of sound wave. Not easy to physics, we note: the sound is mechanical air fluctuations that can be caught by a special device - microphone.
• Air fluctuations also cause vibration with sound frequency of physical objects: glass, walls, some other surfaces, and therefore, removing these oscillations from the items themselves, you can also get a sound "picture" of the surrounding space. This feature is based on special equipment for wiretapping at a distance.
• Another way, it is suitable only for listening to the conversation of people - watch the movements of the speaking lips with the simultaneous translation.

These are all known at the moment, ways of remote and secretive listening. In this review, we will not stop at the possibilities of reading from the lips and removal of oscillations from the surfaces of objects. The first of these methods is extremely difficult, because it requires a special kind of skills, and the second is the use of special, expensive and complex equipment.

How does equipment for wiretapping work at a distance

Today it is possible to buy a listener in Moscow and other cities without any problems, however, let's deal with how the devices of this kind work.

The sound can be remotely listen to the following ways:

• Pre-establish the "bug" in the location of the transmitting signal over the wired line or the radio channel to the receiver, the sound will be written through it;
• Establish a radio transmitting microphone on people or a dog, and they, if necessary, will be moved to the place where the conversation is interested in;
• Pre-install a sound recording device (voice recorder) in a place where the dialogue you are interested in, and after removing it and listen to the record;
• Through special devices - microphones of aimed action, listen and (or) record the confidence of the conversation remotely.
• To listen to the conversation in the room, install a sensitive microphone on the wall of a special kind of a special kind of stethoscope.

Consider some of these methods in more detail, namely: radio and directed microphone. It is these two options that got the greatest distribution in practice.

Radio microphone, as a device for wiretapping at a distance

The most common way is to secretly establish a miniature "bug", which is a special microphone and a betrayal signal to a remote receiver. The use of a wired signal transmission line is extremely rare: it is necessary to pull the wire that it is impossible to be done secretly. The greatest popularity is currently used by the GSM mini velvet, which transmits a signal over cellular channels, and therefore, it is possible to listen to a conversation anywhere in the world using a conventional mobile phone.

Let's consider the features of such a device in a practical example, one of which is.

The presented GSM wiretapping at a distance, bugs can be used today at quite an affordable price, and quality and functionality allows you to attribute this device to the category of professional, it can act as an audio alarm and as a device for monitoring the premises and any other places. Two modes are provided in the device: the ability to enable voice, followed by a call to a predetermined cell phone, as well as a continuous wiretapping mode.

The radius of the microphone is 10 meters, and the size of the device (40 * 30 * 10 mm with a weight of 24 grams) allows it to hide it anywhere: bag, clothes, inside the "glove" of the car, and in the room hide so that accidentally find the bug It will be almost impossible.

Opening hours from a fully charged battery in a wiretap mode up to three hours, and in the alarm mode - from two to four days - it all depends on the number of triggers and respectively - the dialing dialing. In standby mode and with a fully charged battery, it is guaranteed from three to five days.

To communicate bug, the cellular channels of the range of 900, 1800 and 1900 MHz, i.e., fully supported in our country.

The range of operating temperatures from minus forty to plus fifty degrees Celsius, i.e. work is possible in any heated and no room, as well as outdoors. The main condition is a stable cellular network.

Many assembly organizations are faced with the fact that one single active microphone, even with outstanding characteristics, is often unable to cope with listening to the accommodation of the room or a large hall.
For large halls, the obvious solution to improving the quality of listening to the entire area will be the use of several microphones. In this case, microphones should be located so that their sensitivity zone closes the entire area of \u200b\u200bthe room and partially overlapped with each other. But then the question of connecting these microphones to the camcorder or audio board is arising.
Simple printing of microphones per audio input will give a bad result, since the line parameters deteriorate (capacity, resistance, inductance) and therefore, there is a deterioration in the quality of the audio signal, and at the moments when, the signals of different microphones will be in antiphase, they will deduct each From a friend, calling some sound failures on records.

Stelberry mixers

To combine and summarizing audio signals from various sources in recording studios, audioomixers of various complexity are widely used.
But for some reason, such a widely known and integral for audio studies the device until recently received the same widespread dissemination in the security and audio-video monitoring environment.
Correct this annoying situation and raise the possibilities of security systems to a new level are called by the models of the Mixers of STELBERRY MX-300, STELBERRY MX-310 and STELBERRY MX-320.
The main characteristics of these mixers are the same, and their main difference is enclosed in the functionality of the settings menu, or otherwise, in the comfort of the settings.
Each of MX-300, MX-310 mixers, MX-320 allows you to connect up to four active microphones to your linear inputs (and not only active microphones) and configure each channel in terms of signal level individually or in comparison with other channels.

In the MX-300 mixer, each channel has its own independent signal level adjustment, and if you need to configure a signal of some microphone or other linear signal source, regardless of other channels, you will have to disconnect them physically, pulling the corresponding connectors from the mixer.
In the MX-310 mixer, each channel is initially configured independently of other channels, and it is possible without leaving the settings menu to listen to the overall sound picture.

The MX-320 mixer gives the user the ability to independently choose which of the four channels will be active, and setting the channels, both independently of each channel from others and compared with one or more channels.
The possibility of this mixer to quickly change the configuration of the channels involved without their physical shutdown will be convenient if the location of the furniture is often changed in some room or the area of \u200b\u200bactive presence of people is often transferred.

Interesting feature of the audio cases Stelberry

Audiomickers Stelberry has such an interesting feature that all these mixers have linear audio inputs and linear audio outputs.
And this feature allows you to build up the structure of sequentially connected audio encoders, connecting the outputs of some mixers to the inputs of other mixers.

That is, if one mixer allows you to connect only four active microphones, then the outputs of four mixers connected to the inputs of the fifth mixer will already allow the cluster of sixteen active microphones.

Choosing a microphone for a large room

What active microphones are best suited for listening to rooms in a bundle with mixers. Taking into account the fact that the background music can play in the hall, the working ventilation or air conditioners can be heard, then this should be exactly the microphones without AGR (automatic gain adjustment) or with a disabled ARU. Only the microphones for the room without ARU will allow you to maintain speech intelligibility in conditions of different ambient noise. If you use microphones with ARU, then the automatic adjustment of the gain will be tuned on the background noise and pull it out to the level of the microphone output signal, and only this noise will prevail on the record, and the useful signal will be crushed.

Listening to long premises and corridors

Complicated indoor acoustics are usually elongated in the length of the halls or corridors, as well as large empty or semi-empty halls, where the sound is provided freely and repeatedly reflected from the walls, gender and ceiling. In such premises, microphones will be optimal along the room or a corridor with a certain step, depending on the sensitivity of the selected active microphones with such a condition, so that there are no deaf zones between the microphones.
For example, in such a long room, when placing microphones on the ceiling with a ceiling height of 2.5-3 meters, M-20 microphones should be located approximately 3-4 meters from each other, and M-60, M-70 microphones, with Disabled ARUs should be located at a distance of approximately 7-8 meters from each other.
In this case, the sensitivity of the active microphones is configured so that they slightly overlap the sensitivity zones of neighboring microphones. Microphones with a fixed amplification, though cheaper, but give more difficulties with the placement settings, due to the need for a more accurate selection of the height of their suspension and the installation step.

Microphones with sensitivity adjustment are suitable better.

Setting the sensitivity of microphones with a small overlap of the sensitivity zone of neighboring microphones will minimize the effect of humidity and echo, and avoid voice failures when moving speaking people indoors or corridor.
Then installed microphones are connected to the mixture, for example, MX-300. And then, already on the mixer, an adjustment of the gain of each channel is performed so that the signals from the microphones were the same volume. And then, at the request of the customer, the signal from the mixer is fed to the autonomous audio board, such as SPRUT-SR, or if a video surveillance is conducted in the room, then the video recorder's linear audio input or a linear audio input of the IP camera is.
Such an example of microphone placement is somewhat conditional as conditionally selected room for example. In fact, in practice, the step and option of the placement of microphones should be seamlessly under each particular room, and the universal "recipe" does not exist here, in each room there will be their own nuances that requires solutions in place.

Listening to trading halls

The trading room is a classic version of the large hall for listening to which one microphone is clearly not enough.
After all, personnel and customers can move freely, complicating the conditions for the audio establishment.
But often, for small shops, the area of \u200b\u200bthe room is not too large, it is enough to place no more than four active microphones M-60, M-70 on the walls or on the ceiling, which will be connected to one mixes, for example, MX-300,
And the combined signal from the release of a mixer is fed to the linear audio input of the SPRUT-SR autonomous audio order.

Microphone accommodation in the hall

If the room is close to the square and the area of \u200b\u200bthe room approximately 250 m² and the height of the ceilings does not exceed 2.5-3 meters, then it is enough to place four M-60 or M-70 microphones, with a disconnected ARU, closer to the ceiling on the walls at points located In the middle of each of the walls. If the area of \u200b\u200bthe room at the ceilings of 2.5-3 meters exceeds 250 m², but not more than 1000 m², then there are still four microphones and one mixer. Microphones M-60, M-70, with disabled ARU, in this case are located on the ceiling in the corners of the virtual square in the center of the hall. There should be a distance of eight meters between microphones in all directions.

Accordingly, if you have a larger area and sufficient audio channels, you will have to increase the number of microphones and increase the number of mixers. And if you have only one audio input for registration of conversations, you will have to increase the structure from

mixers when the outputs of 2-4 mixers are connected to the inputs of the third-fifth mixer. And again, these are general recommendations. In practice, the step and option of the placement of microphones will have to be selected experimentally for each particular room.

Listening to the sector in a huge trading room

For very large trading halls, the zoning of the Choice of sectors is used depending on the categories of goods, and usually one or two managers or consultant seller, which will advise customers and write the goods selected by customers the goods selected by customers. And here, to control the quality of customer service, it would be good to hear how the manager or consultant in this sector communicates with the client, which goods suggests and does it offer at all.

Building the structure of mixers will allow using more than four microphones

Racks and showcases with goods can reach several tens of meters and in the sector there may be several rows of such racks.
Accordingly, here and use the possibility of increasing the structure of mixers to distribute microphones throughout the sector, since one mixer with four microphones is not enough to listen to the entire sector zone.

Typically, such trading halls have very high ceilings, and the walls can be far from the placement of the sector with a group of goods, therefore the microphones on the suspension will be the most rational option. The height of the microphone suspension can hardly depend on the height of racks with the goods. And here it is necessary to understand the dependence listened by the microphone area of \u200b\u200bthe room, from the height of its suspension.

The higher the microphone from the floor, the more frequent step will have to have active microphones so that the deaf zones do not appear between them.
Accordingly, when using a four-channel audio registration, such as SPRUT-SR, you can organize listening to four such sectors with four microphone clusters in each.

Audio surveillance has long been a parable in languages \u200b\u200bboth in Russia and abroad, and his story is longer and richer than that of video surveillance. Historically, the most negative attitude towards it is negative, although, like any tool, audio surveillance in itself is neutral and completely depends on whether it is in whose hands it is. Before the start of the digital technology era, it was supposed exclusively for broadcasting, but the progress, as is known, does not stand still, and now for high-quality sound transmission, there is enough simple Wi-Fi network. About microphones capable of recording IP and will be speaking in this article.

To begin with, let's talk about the relevance of audio surveillance in combination with video surveillance. Many cost cameras without sound (they, of course, cheaper than their sound-insulating fellows) and are satisfied with the damp movie. However, the microphone for the camera carries with them a lot of benefits: first, night time and just illuminated terrain, as a rule, badly affect the quality of the video received. Even taking into account infrared illumination to find a camera that can see well (more than a pair of meters) in the dark - the task is not from the lungs. The sound of the same darkness does not hold back, moreover, at night, extraneous noises are much smaller, and the sound spreads and catches it better. The audio attachment attached to video is also noticeably increases the informativeness - the operator / administrator receives a more detailed picture. Also worth paying attention to the position occupied by the cameras: in order to maximize the area of \u200b\u200bthe room in the frame, they are usually hanging in the corners. Here lies a contradiction between the optimal sound and the optimal video. The sound, being wave of air pressure, generated by the oscillations of any object (for example, voice ligaments), spreads from the source in all directions. These oscillations with a certain frequency and amplitude captures the sensitive microphone membrane, herself fluctuates and converts them to an alternating electric current of different voltage. So there is a sound recording. In this case, the microphone is hampered by large flat surfaces - ceilings and walls: the waves are bouncing from them, one on the other, generating echo and other distortion. Therefore, the angle of the room is almost the worst position possible for him.

So, a separate microphone for the camera is definitely useful. Where to take a high-quality recording device so that you can bind it to Xeoma? More recently, we found a worthy answer for this question: microphones E-Ear. Production of the company "Electronic Shield". These compact sensitive devices are easy to install both indoors and outside, while getting high quality sound. The set looks like this:

It's easy to work with them - add the module to the chain "Microphone" and choose E-EAR in the drop-down list:

From here, we will only need a serial number - copy it to the appropriate settings field in Xeoma. Below we find such a section:

In the graphs, the user's service and mediaservice address indicate the IP address of the computer with Xeoma (if networks are different, then the server will need static external IP), in the mediaservice port, specify any free port. We are also convinced that in the column the choice of service is 3 MediaService. In Xeoma we get this picture:

The sound channel number determines which from microphones to listen, because several can be connected to one device.
All is ready! Connect "Microphone" to the already existing module "View and Archive"And the sound recording will be kept in the archive on top of the video.

At the end, you should pay attention to the legal side of the issue. Both video and audio surveillance are directly related to Article 137 of the Criminal Code of the Russian Federation "Violation of Privacy", which unequivocally indicates the illegality of collecting information about the privacy of the person without his consent. In this regard, it is especially important to marry the locations of such observation by the corresponding signs / signs.

Thus, a nice microphone for the camera is not a luxury, but prudent investment in your security system.

At the AMPHION FORUM conference a few days ago, a student from the department of systems to determine the invasions of Colombian University Ang Kui (Ang Cui) read a report (presentation slides, PDF) on the use of vulnerabilities in the CNU core (Cisco Native Unix) in Cisco 7975G IP phones, 7971g -Ge, 7970g, 7965g, 7962g, 7961g, 7961G-Ge, 7945g, 7942g, 7941g, 7941g-Ge, 7931g, 7911g, 7906, 7971G-GE, 7970G, 7961G, 7961G-GE, 7941G, 7941G-GE and 7906 .

Vulnerability in CNU is something similar to the recently discovered, that is, it gives an application with the rights of the user's access to the physical memory of the device. In this case, this is possible due to the insufficient security check for the SYSCALL function calls. Thus, the attacker gets the opportunity to rewrite arbitrary fragments of the kernel memory and run any code to execute.

Ang Kui not only described a vulnerability, but also in practice demonstrated how it can be operated, for example, to transform the Cisco IP phone into a hidden listening device imperceptibly for the user. Malicious code receives root rights in the system, accesss the digital signal processor (DSP) and the device control interface. The student has developed a patch that performs the necessary changes in the kernel and DSP, so that the IP phone is imperceptible to the owner includes a microphone and starts to carry out a hidden wiretapping and record.

During his speech, Ang Kui showed how faster it is to install such a patch to any IP phone. To do this, you need to make a small chip with the appropriate firmware, insert it into an Ethernet port of the phone - and take out a second. After that, the phone will "reflash" and can work as a "bug" and writes all the surrounding sounds. Install the patch can also be remotely, via the Internet, although this will have to make some efforts so that the user launches the file to execute. Thanks to CNU vulnerability, any program can get root rights.

Ang Kui also discovered several libraries from third-party developers on Cisco phones, in which there are also vulnerabilities suitable for operation. Using them, you can try to set the malicious code to the device even without notifying the user. However, information about vulnerabilities in third-party libraries Ang Kui has not yet issued, promising to disclose it at the 29C3 hacker conference (29th Chaos Communication Congress), which will be held from 27 to 30 December in Hamburg.

Cisco has been previously notified of the vulnerability and released the corresponding patch for some phone models (see the CSCUC83860 bug). This patch is recommended to install all users as quickly as possible, since the exploit has already passed into open access. Interestingly, the researcher could not find the files of the new firmware of phones on the Internet, that is, the owners of the devices so simply do not download them. Probably need to handle directly to the manufacturer.

For other models - in particular, 7971G-GE, 7970G, 7961G, 7961G-GE, 7941G, 7941G-GE and 7906 - patches are not released, since the phones are removed from production. Owners of such devices are recommended to buy a newer model.

Vulnerability in IP phones Ang Kui found in the process of working on the Gunman V2 learning project, within which they introduced an update of firmware for the HP network printer into a regular document. After processing such a document, the exploit penetrated the firmware and could distribute the malicious code on computers on the local network. According to the researcher, now most network devices - such as printers and IP phones are vulnerabilities and pose a threat to a local network security.

Ang Kui recalls the history of one year old, when some unknown hackers have penetrated into the SCADA water supply system of one of the American cities and disabled a water pump, having deprived citizens of drinking water.

In the illustrations to the news you can see a familiar model of the IP phone.

Purpose

IP microphone OSA P1LN - This is an independent network device, which has its IP address, and intended for converting an acoustic signal into a digital audio stream, for subsequent transmission through its Ethernet and Internet channels using various protocols on the audio server or video surveillance system for recording, processing and storage.

STRUCTURE

IP microphone P1LN OS is:

COMPARISON

PRINCIPLE OF OPERATION

Advantages of IP microphone

Installing IP Microphone

1st step	2nd step	3rd step
Selecting the installation site and connecting to the local network	Installation on the "Registrar" on the computer	Adding a device to the R-server recording program.
The installation location of the microphone is selected based on the standing task, it is preferably close to connecting to a local network. The IP microphone can be positioned on the table, on the wall, on the ceiling, on the shelf, or in other places most suitable for each specific case.	The installation is made from the CD, which is included with the microphone. Almost any modern computer or laptop can be played as an audio server. After installation, the "All Programs" folder will create a "R-server" folder, in which all the necessary programs and utilities will be posted.	To add an IP microphone, you need to run the "IP Transmitter Service" utility, which will detect a new device on the local network and connect it to the recording program. The default averaged acoust-start parameters are set, which will provide the beginning of the recording when the sound signal source microphone appears.

Settings ip microphone

	- Adding an IP microphone in the service IP of transmitters.
	- Changing the name of the recording channel and configure the recording and sound quality modes for each IP microphone.
	- Online listening to an IP microphone.
	- search for the desired entry in the archive by date and time and saving the desired entry as file.mp3 or.wav

- Install the unique device name.	- Online listening to sound on the VLC player on a computer, tablet and mobile phone.
- Changing the network settings of the device: IP address, mask, gateway, port.	- Connecting an IP microphone to an IP video recorder by RTSP protocol to a separate channel.
- Changing the password of access to the IP microphone.	- integration IP microphone with IP video surveillance for synchronous video recording with sound.
- Navigate the RTSP address and microphone port.	- Binding an IP microphone to any IP camera.

IP microphone firmware options:

Firmware for working with "Registrar"	Firmware for RTSP Protocol
This firmware allows you to use an IP microphone to transmit audio over the local network to the computer. To work in this mode, only the IP microphone isp P1LN and the "Registrar" isp.	This firmware allows you to get a sound with an IP microphone in online mode using a media player VLC, as well as for integrating with an IP video surveillance system using the RTSP protocol.
Video to setting the IP microphone with "Registrar"	Video on setting the IP microphone on the VLC player
	Record negotiations in the manager's meeting room and client
Records conversation between doctor clinic and patient	Record Seller Communication Sellfaking with Buyer	Record the conversation seller of travel agencies and client.	Recording the hotel administrator, fitness club with a visitor

Additional information on the use of IP microphone in practice.
The ready-made solution for recording conversations between the consultant and the client based on the IP microphone P1LN

CONTENTS OF DELIVERY:

• IP microphone OSA P1LN.
• Power Adapter with PoE - 1 pc.
• Network cable (patchcord) 1.2 m - 2 pcs.
• Drive C on the "Registrar" and Instruction

Setting the sound broadcast on the media player

The audio information transmitted from the IP microphone can be listened to the media player supporting the broadcast on the RTSP protocol. Consider an example of the broadcast setting, on the example of the VLC media player.

Run the VLC media player.

Going "Tools - Settings - Water / Codecs", go down at the bottom of the page and install the "RTP" tick over RTSP (TCP) "and close this tab (see Figure below).

After that, select the "Media-Open URL" item and specify the network address of the signal source (IP microphone P1LN) via RTSP protocol. See the example in the picture below.

After entering the address, you must click the button "Play".Media player connect to IP microphone and broadcast audio stream. Volume is installed individually.

In the transmission mode of the audio stream, you can open statistics and see which data stream comes and at what speed. To do this, you need to enter the "Tools" menu and select the "Media File Information" tab. Go to the "Statistics" tab. The window opens, as shown in the figure below.

When switching to the "Codec" tab, you can see which codec uses the IP microphone at the moment of time and what is the frequency of sampling.

The transmission mode confidently works on the VLC media player installed on any phone and computer. The VLC media player program can be downloaded for free android for Android phones or in the App Store (for iPhone).