Category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls. For users who have free, or fixed-price Internet access, Internet telephony software essentially provides free telephone calls anywhere in the world. To date, however, Internet telephony does not offer the same quality of telephone service as direct telephone connections.
There are many Internet telephony applications and hardware available. Some, like NetMeeting, come bundled with popular Web browsers . Others are stand-alone products - ip handset. Internet telephony products are sometimes called IP telephony, Voice over the Internet (VOI) or Voice over IP (VOIP) products.
ISDN is abbreviation of integrated services digital network, an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports data transfer rates of 64 Kbps (64,000 bits per second).
There are two types of ISDN:
Basic Rate Interface (BRI) -- consists of two 64-Kbps B-channels and one D-channel for transmitting control information. Eg: Telstra called On-Ramp x 2.
Primary Rate Interface (PRI) -- consists of 23 B-channels and one D-channel (U.S.) or 30 B-channels and one D-channel (Europe) eg: Telstra called On-Ramp x30.
What is PSTN Lines PSTN lines is a short for Public Switched Telephone Network, which refers to the international telephone system based on copper wires carrying analog voice data. eg: Normal Telstra lines.
Telephone service carried (Telstra) by the PSTN is often called plain old telephone service (POTS)
A private automatic branch exchange (PABX) is an automatic telephone switching system within a private enterprise. Originally, such systems - called private branch exchanges (PBX) - required the use of a live operator. Since almost all private branch exchanges today are automatic, the abbreviation "PBX" usually implies a "PABX."
Some manufacturers of PABX (PBX) systems distinguish their products from others by creating new kinds of private branch exchanges. Rolm offers a Computerized Branch Exchange (CABX) and Usha Informatics offers an Electronic Private Automatic Branch Exchange (EPABX).
Several factors will influence future developments in VoIP products and services. Currently, the most promising areas for VoIP are corporate intranets and commercial extranets. Their IP-based infrastructures enable operators to control who can-and cannot-use the network.
Another influential element in the ongoing Internet-telephony evolution is the VoIP gateway. As these gateways evolve from PC-based platforms to robust embedded systems, each will be able to handle hundreds of simultaneous calls. Consequently, corporations will deploy large numbers of them in an effort to reduce the expenses associated with high-volume voice, fax, and videoconferencing traffic. The economics of placing all traffic- data, voice, and video-over an IP-based network will pull companies in this direction, simply because IP will act as a unifying agent, regardless of the underlying architecture (i.e., leased lines, frame relay, or ATM) of an organization's network.
Commercial extranets, based on conservatively engineered IP networks, will deliver VoIP and facsimile over Internet protocol (FAXoIP) services to the general public. By guaranteeing specific parameters, such as packet delay, packet jitter, and service interoperability, these extranets will ensure reliable network support for such applications.
VoIP products and services transported via the public Internet will be niche markets that can tolerate the varying performance levels of that transport medium. Telecommunications carriers most likely will rely on the public Internet to provide telephone service between/among geographic locations that today are high-tariff areas. It is unlikely that the public Internet's performance characteristics will improve sufficiently within the next two years to stimulate significant growth in VoIP for that medium.
However, the public Internet will be able to handle voice and video services quite reliably within the next three to five years, once two critical changes take place:
· an increase by several orders of magnitude in backbone bandwidth and access speeds, stemming from the deployment of IP/ATM/synchronous optical network (SONET) and ISDN, cable modems, and x digital subscriber line (xDSL) technologies, respectively
· the tiering of the public Internet, in which users will be required to pay for the specific service levels they require
On the other hand, FAXoIP products and services via the public Internet will become economically viable more quickly than voice and video, primarily because the technical roadblocks are less challenging. Within two years, corporations will take their fax traffic off the PSTN and move it quickly to the public Internet and corporate Intranet, first through FAXoIP gateways and then via IP-capable fax machines. Standards for IP-based fax transmission will be in place by the end of this year.
Throughout the remainder of this decade, videoconferencing (H.323) with data collaboration (T.120) will become the normal method of corporate communications, as network performance and interoperability increase and business organizations appreciate the economics of telecommuting. Soon, the video camera will be a standard piece of computer hardware, for full-featured multimedia systems, as well as for the less-than-$500 network-computer appliances now starting to appear in the market. The latter in particular should stimulate the residential demand and bring VoIP services to the mass market-including the roughly ?? percent of households that still do not have a PC.
In the future, it is possible to see one service provider providing both Internet access and telephone communication by integrating data and voice transmission through the IP. This would mean the end of the telephone service as we have known, even though traditional telephone services will survive in a foreseeable future.
The VoIP applications will become only more and more efficient and stable. Better bandwidth utilization would come about with efficient multiplexing of data and voice. Efficiency would mean less expensive and easier telecommunication for the consumers.
Voice quality and the lack of means of commercial deployments are the major concerns that VoIP needs to overcome. Voice quality still lags behind traditional telephones, despite continuous improvements. Technological experts are confident that the voice quality of VoIP will equal that of traditional telephones eventually. Also, despite flood of new applications and devices that try to take advantage of VoIP's huge potential, it will take some time for majority of people to accept and get used to making calls through VoIP.
More user-friendly devices and well-orchestrated promotions will go a long way towards speeding up the adoption process of new technologies. Once VoIP's voice quality equals that of the traditional telephones, and people get used to VoIP devices, the prices of traditional telephones and VoIP telephones should equalize.
There are two other potential issues that VoIP needs to tackle. Like all adoption processes of new technology have experienced, the stance of government regarding the VoIP technology is a big concern. Traditional telephone companies have a lot of clout with government and it might not be so easy for the government to make regulations that will undermine telephone giants.
The telephone giants will protest vehemently if VoIP applications start taking a big chunk of its revenue. The government's subsequent ruling could play a vital role in shaping the future of VoIP. At worst, strict government regulations in favor of the telephone companies would retard the development and adoption of the VoIP applications. The best realistic scenario might be for the telecommunication giants to adopt VoIP and integrate it to their existing business. Also, the issue of wiretapping has been discussed. With better security technology, this issue will be taken care of.
VoIP is a natural outshoot of the Internet revolution. VoIP represents the future now, just like the Internet. However, there probably is only a limited time that it could become the dynamite success that its proponents are hoping. Laser disk technology was not tamed by the resistance of the old videocassette technology. Its fate was decided when a better technology, DVD, was introduced. VoIP needs to become integral to the computing world as soon as possible. Its biggest rival probably is in the process of getting developed. The fate of VoIP will be decided in within a decade. If VoIP applications have not become common to most PC users and corporations within a decade, some newer technology would overtake it.
Digital format can be better controlled: we can compress it, route it, convert it to a new and better format, and so on. We also saw that a digital signal is more noise-tolerant than its analog version.
TCP/IP networks are made of IP packets containing a header (to control communication) and a payload to transport data: VoIP uses it to go across the network and come to destination.
VoIP is becoming a key driver in the evolution of voice communications. VoIP technology is useful not only for phones but also as a broad application platform enabling voice interactions on devices such as PCs, mobile handheld, and many vertical-specific application devices where voice communication is an important feature.
VoIP supports two-way transmission of voice traffic over a packet-switched IP (Internet protocol) network. The first widely used VoIP application appeared in the mid-1990s, with services that enabled Internet users to make free voice calls between specially equipped PCs, or between a regular phone and a specially equipped PC. This was a great way to save toll charges on long-distance and international calls. Today, with rapidly advancing technologies, voice quality on managed VoIP networks can match the public voice network.
The primary reason for VoIP was to provide access to voice communication to anyone in any part of the world with minimal or no cost through the Internet backbone. The future of Internet phone would allow an individual to have a personal number which would enable him to communicate from any part of the world without having to pay exorbitant prices.
In addition to IP, VoIP uses the real-time protocol (RTP) to help ensure that packets get delivered in a timely way. Using public networks, it is currently difficult to guarantee Quality of Service (Qos). Better service is possible with private networks managed by an enterprise or by an Internet telephony service provider (ITSP).
VoIP stands for Voice over Internet Protocol. As the term says VoIP tries to let go voice (mainly human) through IP packets and, in definitive through Internet. VoIP can use accelerating hardware to achieve this purpose and can also be used in a PC environment. IP is a well-known and heavily used protocol is nearly all Internet transactions. It is a protocol that addresses addressing and routing between networks and between hosts.
Since the very early days of distance communication, signals were sent in analog form, in waves. Many years ago, the communication world discovered that sending a signal to a remote destination could have been done also in a digital fashion: before sending it we have to digitalize it with an ADC (analog to digital converter), transmit it, and at the end transform it again in analog format with DAC (digital to analog converter) to use it. VoIP works like that: digitalizing voice in data packets, sending them and reconverting them in voice at destination.
What is Voice over IP?
1. Voice over Internet Protocol tranfers voice through IP packets through the Internet. Voice over IP can use special hardware or a PC environment to achieve this purpose.
How does Voice over IP work?
2. Many years ago we discovered that sending a signal to a remote destination could have be done also in a digital fashion. Voice over IP works like that, digitalizing voice in data packets, sending and reconverting them in voice. Digital format can be better controlled: it can be compressed, routed, converted to a new better format. Digital signals are more noise tolerant than the analog one.
Voice over IP use TCP/IP to go from the origination across the network to the destination. TCP/IP is an Internet protocol with a leading IP packet to control communication and the layload.
The advantages using Voice over IP rather PSTN
3. Using a PSTN line, you typically pay for time you use to the PSTN company. With Voice over IP you can talk all the time with every person you want as far as you want without paying for the time. In addition, you can talk with many people at the same time.
A major advantage of Voice over IP and Internet telephony is that it avoids the tolls charged by ordinary telephone service.
At the same time, you can also exchange data with people you are talking with, sending images, graphs and videos.
Voice over IP to Phone Communication
4. Voice over IP needs a devices as a gateway. The gateway receives packetized voice transmissions from users and then routes them to others, using a carrier system interface, sends them over the public switched telephone network.
The Automated Attendant is probably one of the most recognized applications in the Computer Telephony industry. Working alone or in conjunction with a live operator, the auto attendant answers the incoming call usually before ringing an extension. At that time, prerecorded voice messages are played to the caller offering them a menu of choices for directing their call. "Welcome to the abc company. For sales press 1, for service press 2, to speak to our operator press 3." Once the caller has made their choice, the call is routed to the appropriate ringing extension, where they will be connected to the called party, or presented with yet another series of choices. Anyone involved in business communications today is very familiar with auto attendants, and businesses both large and small can easily take advantage of the technology.
Auto attendants can be very simple, or complex listings of choices that can easily become overwhelming and frustrating to the caller if not properly designed and implemented. Small businesses and even many home businesses are utilizing the auto attendant to not only effectively answer and route incoming calls, but also to give a "corporate" image to their operations. Auto attendants are available that incorporate advanced features such as voice mail, information on demand, and follow-me capabilities
