Introduction:
It is a social communication application based on the circle of acquaintances, and the letter itself is free. With the free number of letters, you can call national landlines and mobile phones for free, call friends with letters all over the world for free, backup your address book for free, automatically identify friends with letters, and so on.
network phone
Basic introduction:
VOIP phone, also known as VoIP phone, is a direct call to the other party's fixed phone and mobile phone through the Internet, including domestic and international long-distance calls. The tariff is 65438+ 00% to 20% of the traditional phone fee, which can be divided into software phone and hardware phone macroscopically. Software phone is to download software from a computer, then buy a network phone card, and then talk to the other party (fixed line or mobile phone) through headphones; Hardware telephone is more suitable for companies, telephone bars and so on. First, you need a voice gateway. One side of the gateway is connected to the router, and the other side is connected to the ordinary telephone, and then the ordinary telephone can be freely called out directly through the network.
Basic terminology
VoIP is to digitize the voice signal, compress, encode and package it, transmit it through the network, and then decompress it to restore the digital signal to sound for the other party to hear.
The basic process of sound from source to destination is:
Sound: Sound waves are converted into electrical signals by piezoelectric ceramics and similar devices.
Quantization sampling: analog electrical signals are converted into digital signals according to a certain sampling method (such as pulse code modulation (PCM)).
Grouping: Digitized voice signals of a certain period of time are combined into a frame, and then these voice frames are encapsulated into an RTP (Real-time Transport Protocol) message according to ITU-T standard, and further encapsulated into a UDP message and an IP message.
Transmission: IP packets are transmitted from the source to the destination in the IP network for de-jitter: the de-jitter caused by uneven transmission speed of packets in the network is removed. A complete IP telephone system that can be operated on a large scale includes the following technologies (incomplete for the time being): address speech codec echo cancellation and echo suppression transmission IP message delay control function to jitter IP message function.
Voice gateway: an electronic device that enables ordinary telephones to make calls through the network; According to the number of telephone users, there are one voice gateway, two voice gateways, four voice gateways, eight voice gateways and so on.
Development history
transmarine
1995.2 "IPhone 1.0" was launched by Israel VocalTec company, and the world's first internet voice transmission software was born. IPhone can be said to be the prototype of modern IP phone.
1996.7 American IDT company released the simplex test version of Net2phone, and the world's first VOIP phone was born.
1996. 1 1 American IDT company officially released the full-duplex version of Net2phone.
1997.2IDT Company announced that the call volume of Net2phone reached 2 million times, and the commercial service was initially successful.
China
1997.7 (founder is a college student named Chen Yu) began to promote Net2phone to customers in China, becoming the earliest service provider in China.
1997.7. 12 This website developed the first Net2phone user in China. At that time, the international call charge in China was 15 yuan/minute, and customers saved thousands of dollars every month after using it.
1997.7-8 This site promotes Net2phone to major domestic international trading companies.
1998. 1 Net2phone sold on this site was resold and rented by some users, among which Fujian Chen brothers were arrested and fined by Fuzhou Public Security Bureau. This case is called "the first IP phone case in China".
1998.3 Tianjin Furuitai Technology Co., Ltd. preempted the exclusive agency of Net2phone in China, and monopolized the domestic Net2phone market from 1999 to 200 1. During this period, Net2phone developed rapidly in China, reaching 200 1, and the VOIP calls transmitted through Net2phone exceeded 1 100 million minutes. During the period (1999), the founder successfully localized the 9.6 version of net 2 phone, which enabled Chinese people to use VOIP phones for the first time, greatly promoting the development of Net2phone market in China. During this period, the long-distance telephone charges of China Telecom had to drop again and again. Under the pressure of the market, IP phones were also introduced.
200 1.8 Due to serious disputes, all Net2phone calling cards sold by Furuitai Company were declared invalid fake cards by American IDT Company, and tens of thousands of domestic users suffered direct losses. Furuitai Company was revoked by American IDT Company.
200 1-2003Net2phone tried to cooperate with China Jitong and other companies, and finally chose China Technology Innovation Co., Ltd. with government background as its general agent in China.
Since 2004, the new e phone has been established in June 2004 +065438+ 10, which is a joint venture between China Tietong Shaanxi Branch and Shenzhen Huawei. With an investment of nearly RMB 30 million, the whole platform is the earliest and most stable operator platform in China. It is the only VoIP phone in China that uses voice system to query and recharge, and the phone bill is valid until June+February 2020, 365438+. Today, the new e-link has become the largest brand in the industry! It is far ahead of any similar products in the industry with its super stability and absolute advantage of 5 million online capacity!
The Ministry of Information Industry first deployed two fixed-line operators, China Telecom and China Netcom, to carry out VoIP pilot projects in four cities across the country, among which Shenzhen, Guangdong Province became one of the pilot projects. Some insiders believe that with the test, the industrial policy of VoIP is expected to be clear soon.
The experiment is to explore the business model comprehensively.
With the approval of the Ministry of Information Industry, China Telecom has carried out VoIP-based experiments in Shenzhen, Guangdong, Shangrao, Jiangxi, and local networks of China Netcom in Changchun, Jilin and Tai 'an, Shandong, focusing on PC-phone.
According to the arrangement of the Ministry of Information Industry, the tariff plan during the trial period was decided by China Telecom and China Netcom Group Company through consultation and reported to the communication management department for the record. A related person from Guangdong Telecom told the reporter that VoIP is very different from traditional long-distance and IP long-distance. Take the long-distance call from Guangzhou to Hong Kong as an example. The cheapest charge for traditional long-distance telecommunication service is 0.45 yuan/minute, but the cheapest VoIP on the market is as low as 0./kloc-0 yuan/minute. It is reported that the trial VoIP in Shenzhen can call fixed telephones and mobile phones in any area, and the cost is 0.2 yuan per minute.
Because voice calls are transmitted over the Internet, VoIP is considered as a subversive alternative to traditional telephone services. It is understood that according to internationally recognized classification methods, VoIP has four implementation methods: Phone-Phone, Phone-PC, PC-Phone and PC-PC. However, in the Catalogue of Telecommunication Services issued by the Ministry of Information Industry of China, IP telephony of telephone-telephone and PC- telephone is clearly defined as the first kind of basic telecommunication services, and only a few basic telecommunication operators are qualified to operate at present. Whether the other two forms of expression belong to basic business or value-added business has been inconclusive.
At the same time, in recent years, some VoIP "talk bars" have sprung up rapidly in schools, residential areas and industrial areas. According to the person in charge of Shenzhen Zhongkuan Technology, unlike the traditional "IP public telephone supermarket" that emerged a few years ago, the operating cost of VoIP is lower and the entry threshold is lower. As long as a computer, a broadband, several telephones and a billing software and voice gateway can run, network companies can provide technical support to franchisees or operators. Because making phone calls is as convenient as usual, online "Talk Bar" quickly occupied the market of low-income people and migrant workers, and had an impact on the traditional telephone business.
"For ordinary people, saving money is of course welcome. This market is very big! " The reporter saw on the Internet that there are countless websites promoting "VoIP" investment projects, and Guangzhou X Sound Network Company is one of them. "As long as you need 980 yuan, you can become a municipal agent." "Can be used in enterprises. The market retail price is 0. 15 yuan/min. The monthly telephone traffic of a large enterprise is at least 50,000 minutes, with a profit of 0.065 yuan per minute and 50,000 minutes. The monthly profit is 3,250 yuan, and the annual profit is 39,000 yuan. " "No risk, wait for money, make money every day, and make money every month." The company also claims to cooperate with telecom operators to authorize agents, and at the same time, it gives agents and investors various joining concessions and technical support.
After several years of development, although VoIP has been widely used, the VoIP business is still in a "gray area" at present, without legal restrictions and licenses, and the VoIP "Talk Bar" appearing in the market has no business license. In addition, VoIP itself has inherent defects, and the call quality is affected by the network quality, so it can't be used when the power is cut off, and its clarity is different from that of traditional fixed telephone. Secondly, VoIP still has the risk of being eavesdropped. Because there is no policy support and protection, investors should not invest rashly, although the VoIP business is developing rapidly.