【 Weak current College 】 on multiple lines system building intercom system and ordinary building intercom system (go

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Panoramic view of intelligence industry, the actual realization of the intelligent community almost none. The reason is that although understand intelligence is the trend, it is imperative, but also keen on dogma "boilerplate" perspective, see the "size", on "qualification", on the "price", the essence of the intelligent construction, the intelligent can achieve fundamental basis — across the technology industry's highly integrated system integration technology, evaded, turned a blind eye. Intelligent construction time became a bargain trade, it seems that everyone can provide. Results? a patchwork of "hybrid" model of intelligent systems, both lost enormous intelligent action and results, and a waste of developers and the community of valuable resources. In particular due to technical reasons with intellectual property and inheritance, because many systems are not the appropriate technical support and after-sales service to the effective operation and cannot be the system upgrades and expansion, thus becomes a no-compromise "display" and burden, a direct result of the small number of people who do not know the truth about smart technology of misunderstanding and suspicion of intelligent community life.

First, sound, video and control signals in several common transmission mode

First, in order to let you more easily understand building intercom system and ordinary building intercom system between, let us first understand the audio, video and control signals in several common transmission mode:

(A) audio transmission, usually divided into three

First, the audio does not make any changes in the way of baseband transmission;

Second, through the FM or am transport modes;

Third, the audio signal into a digital signal of a digital audio signal transmission mode.

1. audio not any change baseband transmission mode

Because the audio signal doesn't need to be converted to other transport modes, so that the audio signal of the circuit is simple, low cost, is now building intercom system is widely used, but the drawback is: transmission distance short, once you are outside interference and not easy to eliminate the need for separate audio signal transmission.

2, through the FM or am the audio signals are converted to RF signal transmission mode

This approach is widely used in radio and TV signal transmission of audio, its characteristics are: audio signal transmission distance, using FM mode transmission of audio signal strong anti-interference ability, low distortion, clear sound quality. Disadvantage: in transmitting and receiving equipment, an increase of the modulation and demodulation circuit, price compared to the first way to high, but at the same time transmit a multi-channel audio signal modulation.

3, the audio signal into a digital signal of a digital audio signal transmission mode
This kind of transfer is complete the audio signals into digital signals, the quality of its audio signal depends on the audio signal acquisition accuracy, the higher the acquisition accuracy, the greater the volume of data, signal acquisition and higher cost reduction circuit, but digital signals during the transfer process, there will be no loss, this type of audio signal transmission, digital stored program control switches in wide use, but in actual use, due to the digital audio signal with a relatively small amount of data, in a line, you can transfer multi-channel digital sound signals, or you can also transfer other data or image signal.

(Ii) a video signal transmission, usually divided into the following

First, the video signal baseband transmission;

Second, the video signal modulation into RF signal transmission;

Third, video signals into digital signals transmission mode.

1, the video signal baseband transmission mode

This kind of video transmission mode on the camera out of the image is not used for any of the handling, directly through coaxial cable transmission, its characteristics are: video signal not to make any changes, omit the video signal conversion and reduce production costs related to equipment, the disadvantage is that the signal transmission distance short, despite enlargement, the transmission distance is less than 1KM, baseband transmission of video signal is interrupted, it will be difficult to eliminate, such transmission is now building intercom system widely used.

2, the video signal modulation into RF signal transmission mode

This type of transfer method converts the video signal, as amplified RF signals, use coaxial cable can be up to the most distant, but its 5KM transmission equipment needs related to the modulation and demodulation circuit, costs more, this approach is widely applied to the transmission of television signals.

3. video signal into a digital signal transmission

This is a video transmission of video signals to digital transmission, but because of the video signals into digital signals, data quantity oversized, related conversion equipment cost is too high, in the ordinary civilian systems are generally not used this way.

(3) control signal transmission, typically control signal transmission, RS422, RS485, RS232 several common data transmission mode

RS422 full-duplex data transmission, the transmitted data cable General alone five core signal line, wire, only a few promixity system in use (such as the Beatles, the induction card system uses this signal transmission).

RS485 half-duplex data transmission mode, wire less the transmission distance is less than 1.2KM, access device generally not more than 50 units, such as device more, must be divided into multiple interface management, generally use two cores, but more complex, such transmission in building intercom induction card, access control, meter reading, warning system more generally.

RS232 generally intelligent device and communicates with the computer, its characteristics are signal transmission distance short, in General, data transmission is not more than 10 meters, but are intelligent devices and computerJoin universal use.

In the last two years, because LONWORKS signal control technology widely spread, more and more community intelligence factory, but its dedicated control chip prices high, the network itself can only transfer data signal, audio and video signal transmission in its inability to limit its community of intelligent systems, particularly for its building intercom and monitoring system.

1. ordinary building intercom commonly used signal transmission

In the present building intercom system, since the cost of production and technology, audio and video generally using baseband transmission mode, data signal is usually the way with RS485 transmission, therefore, a general building intercom system, usually at least a four-core wire (a audio cable, two signal lines, a ground wire) plus one video cable transmission mode. This kind of signal transmission cable and wiring complexity, signal transmission distance short and high costs, wiring, debugging difficult. In-line networking mode, add the line of transmission distance, increases the chance that the problem occurs. Once a network failure, less then half-days, then the manufacturers meet and guidance also takes a few days to repair the system. Community property management, intelligent systems maintenance too dependent on manufacturers, once the manufacturer service to keep up with, community of property management brings many negative effects, according to the China property market report, the intelligent community three to five years 35% or so of system crashes, and 30% of the system is not functioning properly, only 20% of the system to normal use.

2-wire system for building intercom system usually uses the connection modes

A backlog of signal cable with screw terminal, the benefits are: pressure connection of the wiring relatively reliable. However, easy to pick up the wiring fault lines, in particular the system installation, commissioning, maintenance, a lot of trouble.
Another is the use of air on the connector plug for connection. It is the use of air on the joints of the connection methods, although the installation, removal device speed, to debugging and maintenance, repair, but the temperature and humidity high area, not because when the temperature and humidity is high, the butt of metal connector, easy oxidation, moldy, resulting in poor contact, so that the system failure rate increases, many project examples demonstrate that, in a number of high-temperature, high humidity areas, the half-year, slow is one to two years, these failures will have multiplied.

3, the system uses the connection modes

System of signal transmission networks and devices are all designed for two-way CATV network design joins devices, connection is stable and reliable, good sealing, signal lines have good shielding effect, moldy and connector plug, remove easily. Outdoor waterproof connector, long-throw into the water will not make any fault line.

Second, many wires doorphone system limitations

Networking is bus structure, there is only one public channel, at the same time there is only one central administration machine or fence gate machine being used, owing to the severe congestion. Although the community has more than one central administration machine (available in the community wuyeguanlizhongxin or monitoring Center accepts user calls and alarm information, call, call intercom) and multiple fence gate host (used in the Community importers call household use), they will not be able to play. Therefore, some manufacturers to develop multi-channel bus system programmes to address the above multiple wires doorphone system for single-channel, (for example: some manufacturers lasted two years, the development of the realization of this way of 980BM2), but in the end because wiring are too complex to give up this kind of design.

General building intercom system channel — — gate machine and indoor extension and Center third-party call or two-party call when other extensions are a function of self-locking phenomenon.

Signal transmission distance short — cannot exceed the size as the community 1KM expanding, can only be divided into regional independent management, cannot achieve the true meaning of networking.

Cabling complex — difficult to upgrade and add other features.

Lightning performance difference — more wire of building intercom system, each of the core wire were required to increase mine components, components due to the expensive, makes the system expensive equipment, General manufacturers are eliminates this device.

III. building intercom system advantage

The system does not change the ordinary building intercom system function and structure, based on the use of cable TV signal transmission technology, audio, video and data signals into different frequency RF signal, transmitted on a coaxial cable, greatly simplifies wiring, making building intercom system installation, commissioning and maintenance easier, more to avoid the above ordinary building intercom system often abuses, and general building intercom, in contrast, has the following advantages:

(A) convenient installation and debugging

Use two-way CATV network development building intercom system, the entire community network is a tree structure, with multiple channels to transmit signals, audio, video and data signals using modulation transfer enables community networking no longer distance and size restrictions, installation and very convenient. Community within the unit, Community importers and the walls of the door the host as well as for community management of the Central Administration machine can be one of the nearest access network. And Central Administration machine and the fence gate host can at the same time and in the community call for different users, breaking the bus networking mode fence gate host and Admin Center using the mode when the interlock. Enable Community wall door host, we reach the pass, and other functions really practical.

(2) network open

System to two-way CATV channel Division to the building intercom system, taking into account the normal operation of large community, with a flat structure, the amount of data may be too large to cause network congestion, have the systemSame time waiting for the device. "" System in building intercom system, based on the building intercom system to the actual requirements of the entire community is divided into three-tier structure: a first level as a unit system; a system for the area at the second level; third-level system for the entire community. The same level of the signal path between the use of the same through all levels of signal control switch signals at all levels, at the same level of isolation of signal transmission and intercom are completed within the same level, when necessary and to the outside world for signal Exchange, through the signal at the control switches and other information exchange at all levels.

(3) system capacity

The entire community using eight-bit encoding scheme for interval codes, in the first level of unit system uses four-digit code to general use two bits represent the floor number, room number two bits; in the second level cluster system using three-digit code is used to represent the unit number; in the third level of the Community system, using an encoding used to represent a piece of code. That is, each community can be divided into nine regional systems, each cluster system to 999 units, each unit has 9801 households. The entire community can have a maximum 88120791 households.

Tablet No. + country code + area code + building unit numbers + floor + room number

A decimal three decimal four decimal

(Iv) the system hierarchy is strong

In each level in the system can use up to 8 stations, 8 hosts. That is, each unit system use up to 8 stations, eight danyuanmen host; each branch systems with up to 8 stations, eight branch entrances hosts; the whole community can use 72008 management machine, with a maximum seating capacity of 8991 units, use 80919 danyuanmen host; each community system with up to 9 community management machine, 9 community entrances and host. For small and medium-sized community according to the actual situation of the community, generally only one level or levels that fully implements the functionality required by the user.

(5) networking distance long

General building intercom system is generally due to the direct transfer of data and video baseband signal, networking distance is very difficult to over one kilometre, and system data, voice and image signal is modulated, networking distance usually ranging 5KM. Such as fibre, community networking is no longer limited by distance, and the larger community, it and general building intercom system's strengths compared to the more obvious.

(6) expansion.

System uses small signal transmission and amplification of the form, so the device access in numbers is not restricted. And 485 system generally each computer's 485 interface with more than 40-50 pieces of equipment. For building Visual intercom system (promixity systems, automatic meter reading system, the three-meter and alarm system, etc.), the addition of phase II, phase III project, you only need to increase the user's equipment, without the need to increase the management center equipment.

(VII) networking features strong

As a multi-channel system, this enables the networking of building intercom system, development of practicality with a high degree of households and families call feature, enabling multiple fence gate host at the call of the household in the community. Has the information publishing, image storage, and other functions.

(8) wiring simple

General community intelligence system independently of General individual subsystems, has its own independent network cable. The slightly larger when the community, the more intelligent system, into the various subsystems wuyeguanlizhongxin line up to hundreds of root. As in monitoring system using the traditional method of wiring, when the watch is 100, regardless of the control and power cables and is intended for use only by wuyeguanlizhongxin video line must be 100 root. Combined with the background music, the three tables set down, alarm, building intercom, etc., so that the subsystem line wuyeguanlizhongxin wiring clutter. The system only needs a few root line into wuyeguanlizhongxin to achieve the above requirements, and can be integrated into the broadband network for home intelligent control and online shopping and e-commerce functionality.

9. easy maintenance

Two-way CATV network for the tree structure, the system runs with computers on the network devices in real-time detection, and timely detect the device and a computer answering under devices, but also can easily tell system network failure points of failure. Find the fault point and your computer will beep to inform property managers timely repair, in the user not found, the device has been repaired. Thus substantially improves the level of property management, reduces the difficulty of property management, variable passive service for active service. Product manufacturers are available through the Community Center computer Internet interface or telephone interface, remote detection of the community network, to guide the user on the system installation, commissioning and maintenance. You can make timely after-sales service, and significantly reduce the cost of after-sales service.