The program-controlled PBX, which is called the Storage Control switch (which corresponds to the routing logic switch, referred to as the have been supervised switch), is also known as a program-controlled digital switch or digital PBX. It usually refers to a switching device used in a telephone switching network, which controls the continuation of the telephone by computer. SPC is a telephone switch that uses modern computer technology to complete control and continuation work.1 Device type Digital SPC is divided into long-distance switches, local switches and so on. There are also types dedicated to signaling networks and smart nets. [1] In 1970, France opened the world's first program-controlled digital switch, using time Division multiplexing technology and integrated circuit. Then the world was vigorously developed, into the 80 's, programmed and digital switches began to spread in the world.2 device features The basic functions of digital SPC [2] are: Subscriber line access, relay continuation, billing, equipment management and so on. The local switch automatically detects the user's off-hook action, gives the user's telephone back dial tone, receives the pulse signal or the dual tone multi-frequency (DTMF) signal generated by the telephone, and then completes the continuation from the caller to the called number (the called number may also be on the same switch). After the continuation is complete, the switch remains connected until the party that detects the communication hangs up. The part of the conversation is to use the digital switching network in the switch, the PCM method realizes the digital exchange, and the control part is realized by the software by the computer.3 Basic composition The main task of the telephone switch is to implement the communication between users. Basically divided into two major parts: the word road equipment and control equipment. The circuit equipment mainly includes various interface circuits (such as user line interface and trunk interface circuit, etc.) and the switching (or continuation) network; The control device mainly includes the marker and the hair generator in the crossbar switch, while in the SPC, the control device is the electronic computer, including the central Processing unit (CPU), memory and input/ Output device. SPC is essentially a computer-based "Storage program control" switch, it will be a variety of controls, methods of programming, storage, the use of external state scanning data and storage procedures to control, management of the entire Exchange system work.Control EquipmentThe control part is the core of the SPC, whose main task is to execute the storage program and various commands according to the requirements of external users and internal maintenance management, to control the corresponding hardware exchange and management functions. The main body of SPC control equipment is microprocessor, which can be divided into two types: centralized control and decentralized control according to its configuration and control mode of operation. In order to better adapt to the requirements of hardware and software modularization, improve the processing capacity and enhance the flexibility and reliability of the system, the decentralized control of the program-controlled switching system has been increasing, has been widely used partial or complete distributed control mode.Word Road Equipment
The basic function of the switched network is to establish the connection path between the caller and the called user through the control part's successive command according to the user's call request. In the crossbar switch it uses a variety of electromechanical connectors (such as crossbar, encoder, reed, etc.), in the SPC switch mainly by the electronic switching array composed of an air separation switch network, and by the memory and other circuits constitute the time Division continuation Network.
Interface device is the interface between digital SPC and peripheral environment, and its function is to accomplish the conversion of external signal and internal signal of switch. The main interface equipment of digital SPC is the user circuit, relay circuit and signaling transceiver device.
(a) User circuitThe role of the user circuit is to achieve a variety of user lines and exchanges between the connection, often referred to as the user interface circuit [3] (Slic,subscriber line Interface circuit). Depending on the switch format and application environment, there are many types of user circuits, for a program-controlled digital switch, there are analog subscriber line (ALC) connected to the analog phone and the digital subscriber line Circuit (DLC) connected to the telephone, data terminal (or terminal adapter). The analog user line circuit is the interface which adapts to the simulation user environment, its basic function [4] has:. Feed (Battery Feed): In the telephone communication, the switch through the user line to the common electric phone DC feed; overvoltage Protection (overvoltage Protection): Because the user line is outside the perimeter, so may be subjected to lightning or high-voltage power attacks, the switch is strictly prohibited to enter the high-voltage , which can damage the internal device of the switch. To prevent the switch from being damaged by voltage shock or overvoltage on the user's line, it must have overvoltage protection. Ringing (ringing): Feed the bell stream to the called user's telephone, the bell flow voltage is usually provided by relay control or high voltage electronic device to the telephone. Monitoring (supervision): To complete a phone call, the switch must be able to correctly determine the following 3 scenarios on the user's line. A) the status of the pick-up machine of the user's phone. b) Dial pulses issued by the user's telephone (number plate). c) input signal of coin, magnetic card and other telephone. The judgment of the above-mentioned user lines can be realized by monitoring the on/off of the DC Loop current on the user line. When the user hangs the machine idle, the DC loop disconnects, does not have the feed current; Conversely, when the user picks up the machine, the DC loop is switched on, and there is a feed current. Codec (CODEC): The use of encoders and decoders (CODEC), filters, to complete the voice signal module and digital-to-analog exchange with the digital switch network interface. Hybrid (Hybrid): 2/4-wire conversion of the user line to meet the requirements of codec and digital switching for four-wire transmission. Test: A test port is provided to test the user's circuit. These 7 functions are often represented by the first-letter abbreviation (borscht). For analog SPC, there is no need to encode and decode function, while in digital PBX, in addition to some specific applications of small switches using incremental modulation method, most of the other uses PCM codec. The digital subscriber line circuit is an interface set up to accommodate a digital user environment, which is mainly used to connect to various data Terminal equipment (DTE) such as computers, printers, VDU, and Faxes via line adapters (LAM) or digital telephones (sopho-set).
(b) access to repeatersThe Access repeater is the interface circuit between the trunk and the switching network, which functions as the conversion of the external signal to the internal signal of the switch, and is used for the connection of the switch trunk. Its function and circuit are closely related to the format of the switching system used and the inter-Office trunk signaling mode. For the Analog Relay Interface Unit (ATU), which is the interface to realize the analog trunk and switching network, the basic functions are as follows: (1). Send and receive line signals indicating trunk status (such as idle, Occupy, answer, release, etc.). (2). Forwards and receives a transmitter signal that represents the called number. (3). Supply the power of the call and the signal tone. (4). Provide the receiving line signal to the control device. For the simplest case, the repeater of a switch is connected with another switch through a real line trunk and uses a user loop signaling, the function and function of the analog repeater is equivalent to a "phone". If the use of other more complex signal mode, the repeater should achieve the corresponding voice, signaling transmission and control functions. The function of the Digital Trunk Interface Unit (DTU) is to realize the interface between the digital trunk and the digital switching network, which transmits the trunk signaling through the PCM related timeslot, and accomplishes the basic functions similar to the analog repeater. But because the digital trunk transmits the PCM group Road digital Signal, it has some special problems of digital communication, such as frame synchronization, clock Recovery, code-type Exchange, signaling insertion and extraction, that is to solve the signal transmission, synchronization and signaling with three aspects of the connection problem. The basic functions of the Digital relay interface unit include frame and complex frame synchronization code generation, frame adjustment, even 0 suppression, pattern transformation, alarm processing, clock recovery, frame synchronization search and inter-office signaling insertion and extraction, as well as the borscht of the analog user circuit, the 8 functions of the digital relay unit can be summarized as gazpacho.
(c) signaling system
Information System (signalling system)In the switch between the parts or switches and users, switches and switches, in addition to the transmission of voice, data and other business information, but also to transmit a variety of special additional control signals (signaling) to ensure that the switch coordinated action, complete user call processing, continuation, control and maintenance management functions. According to the role of the signaling Region division, can be divided into user line signaling and inter-office signaling, the former on the user line, the latter in the inter-Office trunk transmission. If the function of the signaling is divided, it can be divided into monitoring signaling, address signaling and maintenance management signaling.
1 Subscriber Line signalingIt is a signaling that is transmitted between the user and the switch on the user's line. For analog telephone subscriber lines, this signaling includes: (1) Monitoring signaling This signaling reflects the DC user loop through a variety of user status signals, such as the call user off-Hook (off-hook) (outbound), the main call user Hang Machine (on-hook) (cleaning or removal) and called the User off-hook (answer), The user is called to hang up the machine (reverse clear or remove stitches). When the switch detects these signals, it executes the corresponding software, generating the relevant actions, such as the switch to call the user to send a dial tone or busy signal, ring back sound, etc., or to the called user feed ringing signal. (2) Address signaling (called number) This signaling is called by the user to send the called number, the switch is recognized after the control switching network for continuation. There are two types of analog telephones widely used: impulse telephones and dual audio telephones. A. DC Pulse signal dial phone or pulse button-type telephone to send a DC pulse signal, through the telephone Dial control user loop circuit intermittent and generate a DC pulse string. B. Dual-tone multi-frequency signal switching of the fast multi-frequency keypad dial signal sent by the phone, no longer with the pulse and the simultaneous transmission of the "double tone" represents a number.
2 Inter-office signalingThis signaling is a signal transmitted on a trunk between a switch or exchange to control the continuation of a call. Because of the many types of switch format and relay transmission channel, the network covers a wide range, so the inter-office signaling is more complicated. In order to ensure the exchange of communication networks, we must establish a unified international and domestic standards. The inter-office signaling can be divided into road signaling (Cas,channel associated signalling) and co-signaling (Ccs,common channel signalling) According to the relationship between the signaling channel and the Voice path, in the form of channels and signals, Also can be divided into DC, AC and digital signaling. Like the user line signaling, the inter-office signaling can be divided into monitoring signaling, address signaling and management signaling. All kinds of electromechanical switches use along-the-road signaling, although the program-controlled digital switches are still more with the road signaling, but it generally has the function and potential of using the common road signaling. In order to give full play to the advantages of program-controlled digital switching system, it is an important development direction of the current program-controlled switching technology to adopt advanced co-channel signaling. (1). The control signal required by the road is transmitted by the signaling channel itself, or by a signaling tunnel with a fixed connection to it, which transmits the voice message and its corresponding signaling with the same path. (2) The co-signaling system will centralize the various control signals required by a set of speech paths to a common signal data link which is separate from the voice path. CCITT No.7 signaling is one of the most advanced and widely used international standardized common signaling system, because it separates signaling and voice channels, can use high-speed data link signaling, thus has a fast transmission speed, short call settling time, large signal capacity, change and expansion flexibility and high equipment utilization characteristics, the most suitable for program-controlled digital exchange and digital transmission phase junction Integrated digital Network and future integrated Services Digital network. The main functions of SPC: Virtual Switchboard: Instead of switchboard transfer to the word. Self-recording voice: Record Special voice (ex: Hello!) This is Shanghai Far Zhi Network Information Technology Co., Ltd., please dial extension number, check number please dial 0, fax please dial 101) Elastic code: Each extension can be compiled extension number. Level limit: Limit dialing international, domestic, local calls and so on level 7. Relay Hotline: Pick up the machine 9 outside the line. Incoming and outgoing calls: Direct dialing, transfer, group call selection. Plug-in service: In special cases, the switchboard is calling the extension to make strong plug-in calls. On behalf of the long-distance: Switchboard can be used for low-grade extension calls. Distinguish ringing: can distinguish ringing from outside line or inside. Referral transfer: Outside line transfer for consultation and music waiting. Billing method: Anti-pole billing method or delay billing method. Print Selection: Print selection in English and Chinese. Voice mail: Query their own level, number, phone call, date, time and so on. 4 Development status 2009 China produced digital SPC 4.147 billion line, down 7.95%. For the communications equipment industry, the industry boom supporting the main point of two, one is the electronic information industry revitalization plan brings investment opportunities. From the industrial point of view, the revitalization of the electronic information industry planning will be conducive to the upgrading of the telecommunications industry, the communication industry through the industrial structure adjustment to grasp the development opportunities of the industry, thus traction the communications equipment industry profitability has been enhanced. Second, the restructuring of the telecommunications industry and the issuance of 3G licences will increase the amount of telecommunications equipment purchased by operators. With the restructuring of domestic telecommunications and the issuance of 3G licences, domestic telecommunications investment began to accelerate. China's accession to the WTO and the implementation of the national strategic deployment of the western development, so that many switch manufacturers, businessmen will have a golden opportunity, which provides a broad market for the switch. At the same time, because of the continuous technological innovation of the switch manufacturers, especially in the IP field of continuous development and application, so that the switch in a long period of time still has a large market prospects. First, the price advantage enables the switch to have the broader market prospect than the virtual network. Second, from the perspective of using objects, the switch has a larger market than the virtual network. In some industrial and mining enterprises and other units, the call is mainly internal; in the hotel, hotels and other large enterprises and institutions, installation of switches is not only to meet the call needs, but also to establish a good image of the unit needs. In addition, the installation switch can find the telephone number that the user needs by dialing this service desk (for example, in the hotel call the main station), and this virtual network cannot do it. Third, the user switch to the IP domain infiltration, so that the switch has a new vitality. PABX product development will be a major shift, many traditional manufacturers will abandon the past architecture, to support the various server-based architectures and systems of value-added interconnection, this change, so that the re-access to the market-controlled switchboard, communication products in the IP field of the wide use of a positive role in promoting. 2011, the broadband market drivers have not changed, the competitive pressure will continue to rise; FTTH will become the mainstream broadband construction model, broadband construction climax has not yet arrived; the optical communications industry will fully benefit from the continued large-scale broadband construction and determine the growth of the next 3 years. Optimistic about the long-term performance of large-scale broadband construction to the relevant communications enterprises drive.5 Advantages
1. Technical superiority(1) can provide many new user service functions, such as the reduction of dialing, caller ID, wake-up service, call transfer, call waiting and other services, no longer a single voice business. (2) Convenient maintenance and management, high reliability. The SPC can detect and locate faults through the fault diagnosis program, so that the emergency treatment is prompt and timely in the event of failure, so it brings benefits in maintenance management and reliability. (3) Great flexibility. In order to adapt to the change of external conditions of the switch, the new business can only change the software (program and data) to meet the needs of different external conditions (such as the local Bureau, Toll Bureau, etc.). (4) To facilitate the use of electronic components of the latest results, so that the advanced technology of the machine to play.
2. Economic superiority(1) Exchange of equipment. Small size, the use of electronic devices to reduce the volume of the switch, so that occupy a small area of the computer room, power consumption, electronic devices instead of mechanical components, greatly reducing the cost of energy, low costs, with the reduction of IC prices, can greatly reduce the cost of the switch. (2) Line equipment. You can save the user line by using the remote user module and reduce the cost of the line equipment. (3) Maintenance of production. Due to the automation of detection and diagnosis of faults, many maintenance work is reduced and maintenance personnel are saved. As the manufacturing process is simple, the production efficiency is improved.6 Management and maintenance
1.Hardware on the aspects to be aware of (1) room temperature and environment. The SPC has higher temperature and environment requirements for the computer room. The more users, the greater the energy consumption, the greater the amount of heat emitted, so the need to operate in a constant temperature, clean environment. Room temperature to keep at about 20 ℃, if the temperature is too high, will cause the machine cooling difficulties, so that the machine component parameters change, the stability of the circuit is reduced, serious damage to the equipment. Pay attention to the temperature at the same time to maintain a certain humidity room, such as the room is too humid, will make the metal parts of the machine rust, corrosion equipment, and even reduce the line insulation, short circuit and other phenomena. Room is too dry, it is easy to generate static electricity, directly threaten the security of the switch. According to regulations, the humidity of the room should be kept in 40%~60%. Temperature and humidity can be monitored by thermometers and, if necessary, air conditioners, humidification machines or dehumidifier can be adjusted. In addition, the room also requires fire protection, dustproof measures, cable pipe construction after the serious blockage to prevent small animals to enter. (2) Anti-static measures. The circuit of SPC adopts large scale and VLSI operation. The higher the degree of integration, the lower the voltage and impact resistance level correspondingly. Static electricity generated by the voltage can be up to dozens of, hundreds of, thousands of or tens of thousands of volts, such high electrostatic voltage enough to wreck or hit the chip, so the electrostatic effect on the program-controlled program is extremely threatening. Therefore, the room floor requires the laying of anti-static flooring, the crew into the room work to rotation static slippers, touch equipment, Plug and unplug the circuit board should wear anti-static gloves. In the computer room work should not go back and forth run repeatedly to prevent friction to generate static electricity. (3) Grounding facilities. It is generally believed that the anti-jamming ability of digital communication is strong, but for the SPC, the grounding facilities will directly affect the quality of the operation of the equipment, if the grounding facilities are bad, it will cause fluctuation of ground potential, it is possible to make the switch digital circuit operation logic error. In practice, the signal grounding, power grounding, protection grounding and working grounding of the switch are required to meet the standards. At the same time, the reduction of grounding resistance, the addition of coarse grounding wire, the standard grounding is a stable and effective means of machine operation. (4) Electromagnetic environment. Electromagnetic environment is very serious pollution, in the program room and nearby, do not allow the installation of high-power radio, to prevent the impact of electromagnetic radiation on the normal operation of the switch. In the engine room, the switch of various cables and mains AC power cord should be as far away from the long-side laying, so as not to cause electromagnetic coupling or resistance-capacitance coupling interference. When necessary, all types of cables should cross each other.
2.Software management on the need to do a few (1) pay close attention to the operation of the machine, timely detection of various types of alarm information. (2) Often check the operation and maintenance terminal, billing system, desk, printer, etc. are in normal working condition. (3) A variety of different types of spare circuit board is well-kept. (4) After the significant operation, the data of the switch database should be copied and printed in time, and carefully kept in order to be used in case of urgent need. (5) Regularly check the audio wiring rack on the lightning protection devices, security is effective. Prevents damage to the machine by the introduction of alternating current from an outside line due to faulty lines.7 Switch Configuration ZTE ZXJ10 Network Management experiment Simulation system
IntroductionProgram-controlled Exchange principle course is the basic course of communication major, through the combination of mainstream program-controlled exchange equipment for teaching, can effectively enhance the learner's understanding of the principle of program-controlled exchange, circuit-switched network learning and seventh signaling mastery. ZXJ10 Program-controlled Exchange experiment simulation teaching software includes "virtual machine room" and "virtual backstage" two software. The software real simulation reproduces the interface of the ZXJ10 hardware and background 129 server [V10.0.03.04.3] of the program-controlled switching device. The software is the most typical SPC model ZXJ10 8KPSM For example, combined with ZTE Assistant Exchange Engineer Certification examination needs, design simulation program-controlled exchange the most basic functions.
Function IntroductionThe simulation software has the following function interface:? The virtual machine room to the program-controlled exchange equipment know-how is the first step of learning program-controlled switching technology, whether ZTE, Huawei or Bell manufacturers out of the switch-controlled configuration of different, have the same functional unit, in a functionally consistent. Through the software in the virtual room ' hardware observation ' can help customers to observe the equipment hardware, master equipment structure details, the device composition has a more intuitive, more comprehensive understanding. Virtual backend includes experiments, business implementations, and signaling tracking in "virtual backend":? The typical experimental unit--100% to reproduce the configuration process of communication equipment network management, and master the operation data configuration. Through 4 Classic program-controlled exchange experiment software, students can master the design of the program-controlled Exchange system, the opening of local telephone, the learning of signaling knowledge of seventh and the open of the telephone business between offices. Virtual Telephone--Experience the business implementation process How do I verify the results after the data is configured? Instead, pick up the phone and call it directly. The customer simulates the telephone dialing process in the virtual telephone, verifies the result of the experiment operation, and carries on the real experience to the telecommunication service. Fault location tool, signaling tracking tool-if the location device is configured for failure. How to find the error of operation, locate the fault of the configuration? The simulation software provides powerful alarm, call tracking and signaling tracking tools. By learning and using these tools, learners can easily discover errors in the process of the experiment, and deepen their understanding of the theoretical knowledge and practical experience by locating and eliminating the fault points during the operation.
What kind of program-controlled switchboard!
