The company's computer office network construction has begun, but most companies based on computer networks are only limited to data communication, how to carry out various applications in this network, maximize the potential of office networks, make the network Investment brings more returns, this is a very realistic issue. The IP telephony service on this network is an important aspect of expanding the application. It can expand the range of LANs, not only to shared computers, printers and Internet access, but also include telephone services.
The IP phone is a voice service transmitted by the voice signal to the data data package, and the voice service transmitted on the IP network is, that is, through the open network network transmits voice application service system; using the Internet to provide real-time voice services And no longer use a traditional public telephone network (PSTN) to talk a long-distance telephone network. The most prominent feature of IP phones is significantly reduced network operating costs. Because the company's call is conducted on the data online, the only need to pay is the network communication fee, which reduces the spending spending, especially for those who have more branches, regional dispersed, can save large pen Long-distance communications fees.
First, introduced several IP telephone equipment
At present, voice technology and standards on IP online have been basically mature, and the extensive applications involved include VoIP gateways, LAN IP telephone switches (IP PBX), small IP group calls (PC PBX).
1. VoIP gateway
The VoIP gateway is primarily applied to IP telephony between enterprise branches, providing traditional voice interfaces, connecting to an existing telephone switch (PBX) or group phone connection, while passing long-distance calls to IP network (Internet / intranet) ), As shown. The main features of the VoIP gateway application are to make full use of existing network resources, save users' long-distance calls, and combine with the existing traditional telephone exchanges (PBX) or group calls, can gradually transfer traditional languages to IP networks. VoIP Gateway products have been widely used in telecommunications, as a mature IP telephone solution, and is currently popular in large enterprises. Some small VoIP gateways will bring options to SME users, which can generally provide 4 or 8-way telephone relay interfaces, while providing simple routing features and network interfaces, it can be conveniently Connect the phone switch or group phone of the enterprise branch to the IP network.
VoIP gateway
Figure one
2. IP PBX
IP PBX implements end-to-end IP voice communication, and its built-in CTI function can meet the user's business, office, customer service and other application systems simple connection, so that data and voice are transmitted, this is also IP telephony development. The direction.
3. PC PBX
PC PBX combines the characteristics of VoIP gateways and local area network IP phone switches (IP PBX). You can use existing telephone lines and telephone, with the functional interface of desktop computers and telephones, using the VoIP card (ip). Internet / Intranet) Long-distance call for the network. PC PBX products are based on local area network (WAN), WAN (WAN), and Internet-Phone Communications products, which provides small and medium-sized enterprises and office branches with revolutionary voice data solutions, and provides flexibility for customers' future development. The rooms have expanded, so that the growing SMEs can get a wealth of communication environments without high cost costs. It can generally meet the needs of dozens of telephone users, but there are many characteristics of many VoIP products and IP PBX products, especially the characteristics of traditional simulation telephones, making it easier to accept ordinary users. Second, an IP phone implementation case
For a business, you can meet the needs of a normal telephone switch (PBX) in the local internal call. For non-fixed long-distance traffic, if you want to build an IP telephone system yourself, such as IP PBX, it will be difficult to accept in SMEs in the investment. At present, the maximum function of IP phones can significantly reduce long-distance calls. Many companies have their own branches, such as R & D, Sales, and Office ... In a geographic location fixed environment, the VoIP gateway implements IP telephony functions, and the cost of call cost will play an immediate effect. Below we will introduce a specific application.
There is a Taiwanese company, in Taiwan, Dongguan, Guangzhou and Chongqing's own branches, there is a large number of calls, especially the R & D department, and its call is very large. Therefore, it is tried to use an IP phone between various places to reduce communication spending. Before implementing IP telephony services, all places have a perfect local area network, and the broadband access of fixed IP is applied. And deployed a program-controlled telephone switch in the office.
First we have to ensure that there is a network access of fixed IP addresses. It is best to use the broadband. Take Chongqing as an example of Netcom's Internet line, 512kbps bandwidth, and fixed IP there ADSL, is also bandwidth of 512kbps; Dongguan is used by broadband access in the office building; Taiwan has used fiber access, and 2Mbps bandwidth. Because the IP address is the only basis for his transmission packet, if we don't have a fixed IP address, when we use the IP phone function, we need to modify the configuration of the VoIP gateway, this way is very inconvenient for operating. After a basic network condition, our only equipment that needs to be purchased is four VoIP gateways. Fig. 2 is a plan frame.
Figure II
Choosing the right VoIP gateway is based primarily based on its features and prices, Cisco and 3COM have the corresponding products and solutions, but expensive prices make people. Some domestic manufacturers' products, the price will be much cheaper. Generally speaking, due to the maturity of core technologies, the reliability of such products is very high, and it is not worried about the reliability of the product. Of course, the big company's products have more additional features, after all, performance and cost is linear. Common VoIP Gateway products should have the following basic functions:
1. System Features:
The system is based on a Windows NT operating system that runs voice services on the IP online. It is connected to the telephone network or PBX through the E1 relay or analog line, and two standard telephone terminals can be supported by 10 / 100Baset Ethernet through the E1 relay or analog line.
2. network transmission:
The occupied bandwidth of each voice is approximately 8kbps, that is, the transmission of 84 segments can realize the transmission of 84 segments on a 512 kbps bandwidth resource, saving communication resources. 30-120 digital relay, or 4, 8, and 16 analog subscriber interfaces are available to PSTN (by adding backplane extensions).
Has good voice communication quality.
Relay interface support No.1 (R2MF) signaling or No.7 signaling.
Support TCP / IP protocol and ITU H.323 industrial standards.
3. Perfect maintenance management capabilities:
The configuration of multi-upper IP gateways can be provided in the Internet / Intranet environment. It also contains intelligent monitoring,
Remote maintenance, visual control, network function such as a variety of anomalies.
Real-time tracking and reporting of all ports, on / closed, and connection status.
Various lines, such as PBX extensions, simulation subscriber lines and digital relays, can be individually configured.
The company purchased three ordinary VoIP gateways (Figure 3. Backplane of a VoIP gateway), you can support 30-channel digital relay, and 4 analog user interfaces. On Dongguan, because of a small amount of tongs, the office does not install a telephone switch, so the specified phone and fax machine are directly connected to the VoIP gateway, and then access the Internet through the fixed IP broadband in the office building. Taiwan, Chongqing, Guangzhou is connected to the original small telephone exchange and VoIP gateway and then access VoIP to the Internet. Specific settings are not introduced here, quite simple, the installation guide provided by the manufacturer is very detailed.
Figure three
When the IP call system is established, the calls between the company have almost not restricted, and the cooperation between the various departments, especially the R & D department; fully utilize the original network access resources, greatly reduced The company's long-distance call expenditure. Because using this system call, you don't have to pay additional costs. The purchase price of a single device is around 600 US dollars, which is directly purchased in Taiwan, and it is understood in the country, it can be bought around 5,000 yuan. It should be pointed out that the implementation of this program should be carefully calculated. If the call is small, there may be no necessary. The scheme described above is applicable to a large number of calls between branches around a company.
The IP telephone system is increasingly mature, more and more companies are no longer limited to using traditional telephone networks, but more IP phones applications and services. IP phones are becoming an important information transfer and communication carrier, although it is necessary to transfer all speech traffic on traditional telephone networks, but the vitality of IP phones reflect this area will be the development of enterprise applications. direction. David Tucker, General Manager of Cisco Voice Video Division, believes: "The era of IP phones has arrived in advance, so companies have begun to upgrade their systems, and they are not willing to develop behind the times because of solidification of traditional equipment."
