Internet telephony, also known as VOIP phone, is made through Internet Call each other directly Landline telephone And cell phones, including domestic long distance and International call And the tariff is 10% to 20% of the traditional telephone cost, which can be divided into software phones and hardware phones on a macro level. A software phone is on a computer Download software , and then buy a network calling card, and then pass headset Implementation and the other party (landline or Cell phone ) To make a call; Hardware phones are more suitable for companies, Please tell me Wait to use, first to a voice gateway The gateway side is connected router On, the other side is connected to the ordinary phone, and then the ordinary phone can directly call out through the network.

Chinese name: voip
Foreign name: VOIP

alias: VOIP phone
Acoustoelectric conversion: electricity ceramic Scheduling device
Speech coding: G. 711, G723.1, g. 729 a

catalogue

5Safety problem

Principle of telephone

broadcast

EDITOR

voip Through handle Speech signal After digital processing, compression coding packaging, through Network transmission Then decompress, put Digital signal Restore it to sound so the caller can hear it.

One's voice The basic process of getting from the source to the destination is:

Acoustoelectric conversion : Through Piezoelectric ceramics And similar devices will Sonic wave Transform to Electric signal

Quantitative sampling : Will Analog electrical signal According to a certain sampling method ( For example Pulse code modulation , that is PCM Convert to Digital signal

packet : It will take some time digitization After the speech signals are combined into one frame, followed by International Telecommunication Union (ITU-T) standards, these One's voice Frame quilt encapsulation To an RTP (i.e Real-time transport protocol , Realtime Transport Protocol (RealTime Transport Protocol) packet, and is further encapsulated to UDP Packets and IP packets.

transmit : IP message in IP network Transfer from the source end to the destination end to remove jitter: Remove the cause packet In the network Transmission speed The uneven jitter caused by unpacket electroacoustic conversion is a complete, large-scale commercial operation IP telephony The system includes the following technologies (not yet complete) : addressing One's voice Ed decode Echo cancellation and echo suppression transmit IP packets Time delay Control Function de-jitter Indicates the de-jitter function of IP packets

Voice gateway : Enabling ordinary telephones to make calls over a network Electronic equipment ; According to use telephone The number of parts has a mouthful Voice gateway , two-port voice gateway, four-port voice gateway, eight-port Voice gateway Let's wait.

Gateway parameter

broadcast

EDITOR

In pieces Support protocol : MGCP SIP protocol

In pieces Speech coding : G.711, G723.1, G.729 A

◆ Support multiple points Freelink (TM) technology

◆ Support PPP /PPPoE, DNS , DHCP protocol

◆ Have PBX the Basic function : Busy transfer, Fly line , transfer, etc

◆ With escape function, when the network is disconnected, the VoIP line will automatically jump to PSTN The line.

◆ Support 802.1Q/1p VLAN And voice first

◆ Support mute suppression, detection, echo suppression, Comfort noise Generation, packet loss compensation, Gain control

◆ Support DTMF Transmit-receive number

Brief history of development

broadcast

EDITOR

abroad

1995.2 Israel VocalTec unveils IPhone1.0, the world's first Internet Voice transmission software was born. The IPhone was the prototype of the modern IP phone;

1996.7 America IDT Company release Net2phone simplex Beta version The world's first dial-able phone VOIP The telephone was born;

1996.11 IDT has officially released Net2phone Full duplex Edition;

1997.2 IDT announced that Net2phone reached 2,000,000 calls, Commercial service Initial success was achieved.

China

1997.7 (The founder is a college student named Chen Yu) began to China Customers promote Net2phone and become the first service provider to carry out this business in China

1997.7.12 The site developed China first Net2phone User. then China the International call Telephone bill For 15 yuan/minute, customers can save thousands of dollars per month after using

1997.7-8 - Station direction China All major International trading company Promote and promote Net2phone.

1998.1 Net2phones sold on behalf of the site are resold and rented by some users, among which Fujian (Province) the Chans The brother was arrested and fined by the Fuzhou Public Security Bureau in a case known as" China The first case of IP telephony ".

1998.3 Tianjin Freitai Technology Co., Ltd. is the first Net2phone China exclusive Power of attorney And once monopolized the domestic Net2phone market from 1999 to 2001, during which Net2phone developed rapidly in China, and by 2001, VOIP was transmitted through Net2phone One's voice More than 100 million minutes. During the period (1999), the founder successfully translated Net2Phone version 9.6 into Chinese, making Chinese people use the Chinese interface for the first time VOIP Phone, greatly promoted Net2phone Chinese market Development. While... China Telecom Long distance telephone charges had to fall again and again, and under market pressure also launched IP phones.

2001.8 Due to serious disputes, all Net2phones sold by the Freitai company Calling card IDT declared invalid counterfeit cards, tens of thousands of them China The user suffered direct losses, and the Freitai Company was cancelled by the IDT company of the United States.

2001-2003. Net2phone and China jitong A number of other companies tried to cooperate, and eventually chose Chinese technology with government backing innovate Co., Ltd. is its general agent in China.

2004 At the new e-pass voip It was founded in November 2004 by China Tietong Shaanxi (Province) Branch heel Shenzhen Huawei co-created, the entire platform investment of nearly 30 million RMB It is the earliest and most stable operator platform in China, and it is the only one in China that uses voice system to query the recharge network phone Validity period By December 31, 2020, after a year of testing, the company officially opened to the whole country in September 2005, and was fully responsible for the market expansion in China. Today, new E-tone has become the largest brand in the industry! It has super stability and 5 million online capacity Absolute advantage Far ahead of anything in the industry Similar product !

Ministry of information Industry First deployment of China Telecom and China Netcom Two major fixed-line operators are operating in four cities across the country VoIP ( voip Pilot, which Guangdong Shenzhen Become one of the pilots. There are insiders Thought, as the tests went on, voip the Industrial policy Hopefully it will be clear soon.

Experiments are for full exploration Business model

Approved by the Ministry of Information Industry, China Telecom in Shenzhen, Guangdong and Jiangxi Shangrao County , China China Netcom in Ji Lin Changchun and Shandong Tai 'an the Local network Within the scope of the VoIP pilot, the focus of the trial is limited to the way computers and phones (PC-phones) are conducted.

According to the arrangement of the Ministry of Information and Industry, the tariff plan during the test period is determined by China China Telecom and China Netcom Group Corporation shall decide on their own and report to the communications regulatory department for the record. Guangdong Telecom One person told reporters that Vo IP With traditional long-distance and IP long-distance difference is larger to Guangzhou For example, the cheapest traditional long-distance service charge of telecom is 0.45 yuan/minute, but the cheapest VoIP on the market has been as low as 0.1 yuan/minute. Word is, in Shenzhen Under test voip Can be called to any area of the fixed phone and mobile phone, the cost is 0.2 yuan/minute.

As is through Internet Transmit to Voice call , voip It is considered to be a disruptive alternative to the traditional telephone service. It is understood that according to the internationally recognized classification method, there are four ways to implement VoIP: Phone-Phone, Phone-PC, PC-Phone and PC-PC. In the "Telecommunication Service Classification Catalogue" issued by the Ministry of Information Industry of China, the IP telephone of Phone-Phone and PC-Phone is clearly defined as the first category Basic telecommunication service There are only a few foundations Telecom operator qualified operate . And the other two forms of expression belong to Basic service still Value-added service The jury is still out.

Implementation mode

broadcast

EDITOR

alitong (English name: alicall) is Hong Kong telecommunication Operator Alitong Technology Co., LTD. ( Telecommunications Authority of Hong Kong PNETS License No. 1368) an Internet telephony product launched globally. Alitong uses the world's most advanced voice platform (with P2P as the main technology), and has been focusing on providing customers with high-quality and cheap professional voice communication services. And it's simple and easy to operate, Speech encryption Real-time billing, voice quality comparable to traditional phones, no matter when and where, you only need to access the Internet Personal computer Or mobile phone, you can achieve as low as 5 cents to call the fixed and mobile phones in more than 300 countries/regions, so that you can communicate with friends and relatives thousands of miles away as clear and natural as face to face. There are three ways to call:

PC to PC

This way is suitable for those who have Multimedia computer ( sound card Must be Full duplex Be equipped with microphone And users who can connect to the Internet, the premise of the call is that both computers must be installed in the same set voip Software.

This kind of web peer-to-peer Mode of call, is the prototype of IP telephone application, its advantages are quite convenient and economic, but the disadvantages are obvious, that is, the two sides of the call must agree in advance at the same time online, and this in the ordinary business field is quite troublesome, so this way can not be commercialized or enter the public communication field. This method of calling is completely free of charge.

Simply put, the process of making a phone call between a computer and a computer on the Internet consists of the following five implementation steps: ^[1]

1, First, through the local machine sound card to sound Information record Come down;

2, Use software to convert sound files into a compressed Data file ;

3, through the network to send data files to Answer the phone A party to;

4, the other software will restore the data file to the sound file;

5. Play the sound through the other party's sound card.

PC to Phone

As the advantages of IP telephony are gradually recognized, many Telecom company On this basis, the development is carried out, so as to achieve the adoption computer Call a regular number. During the call, the computer connects to the Internet and dials to the other party through the voip server Telephone set Up. ^[1]

Act as Calling party the computer , required to have Multimedia function Can connect Internet And to install IP phone software.

The benefits of making calls from computer to local types are obvious, Called party You can have a normal phone, but in addition to paying Internet and local phone charges, you must also pay IP phone software companies. This method is mainly used to make calls to foreign countries, but this method is still very inconvenient and can not meet the needs of the public to talk at any time. Such calls can cost 5 cents a minute for long domestic calls. International call Up to 98% off.

Note: Install via mobile phone sip Software, there is network If you call the other party's mobile phone, you will only charge 5 cents per minute for domestic long-distance charges. Up to 98% off international calls.

Phone to Phone

This method is called "telephone dialing" and requires the support of the IP phone system. Normal Telephone subscriber By local call Dial connection To the local IP address Telephone network Tube, enter the account, password, confirm after entering the called number, by the local IP telephony gateway Connect the IP phone gateway closest to the called number, and then the NMS passes through the local phone network Link together The called number of the user is thus completed Telephone communication . ^[1] An IP phone system generally consists of three parts: telephone, gateway and Network manager . Telephone means you can go through Local telephone network Local link gateway Telephone terminal; The gateway is the interface between the Internet network and the telephone network, and it is also responsible for carrying out Speech compression ; The network administrator is responsible for user registration and management, including access users Identity authentication Call logs with detailed data (for billing) and so on.

Safety problem

broadcast

EDITOR

With the increasing use of voip, voip Safety problem Also increasingly prominent. Security is one of the necessary and important components of voip. How to protect the privacy of voip voice information has become a problem that needs to be overcome in the development of voip. Voip encryption is a technical means to ensure the security of voip. IPSec , Secure real-time transport protocol SRTP and Virtual private network .

Hit the road

Growth task Introduction to editing Editing rule Edit by oneself

I have a question.

Content questioning Online customer service Official post bar feedback

Complaint and suggestion

Report bad information The article was not appealed Complaint infringement information Blocked query and unblocked

Beijing Public network Anbei 11000002000001