środa, 18 kwietnia 2012

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niedziela, 16 października 2011

VoIP Gateways b

A VoIP Gateway (Voice over IP Gateway) is a network device that helps to convert voice and fax calls between an IP network and Public Switched Telephone Network (PSTN) in real time. It is a high performance gateway designed for Voice over IP applications. A VoIP gateway can typically support at least two T1/E1 digital channels. Most VoIP gateways feature at least one Ethernet and telephone port. Various protocols, such as MGCP, SIP, or LTP can help to control a gateway.

VoIP Gateway Benefits

VoIP gateway’s main advantage is that it connects existing telephone and fax machines through traditional telephone networks, PBXs, and key systems. This makes the process of making calls over the IP network familiar to VoIP customers.

Voip Gateway Voip Iad Ata Ip Phone VoIP Gateway

VoIP gateways end telephone calls, provide user admission control with an IVR (Interactive Voice Response) system, and provide accounting records for the call. Gateways also help direct outbound calls to a specific destination or end the call from another gateway and send the call to the PSTN.

VoIP gateways play a major role in enhancing carrier services, support the simplicity of telephone calls for less, and give easy access. Flexible call integration has been developed for less, which enables programmable call progress tones and distinctive ring tones.

VoIP Gateway Functions

The VoIP gateways’ main functions include voice and fax compression or decompression, control signaling, call routing, and packeting. VoIP gateways are also power packed with additional features such as interfaces to external controllers like Gatekeepers or Softswitches, network management systems, and billing systems.

Popular VoIP Gateway Products

Cisco Small Business Pro SPA3102 Voice Gateway with Router

Cisco Small Business Pro SPA3102 Voice Gateway with Router offers amazing features to any small business or home user looking for an advanced voice gateway. The SPA3102 can be connected to any standard telephone or fax machine in order to transmit the data over the Internet to the end-user. The SPA3102 also reroutes mobile telephone calls to and from cell phones through the Internet in order to prevent customers from having to pay for both long distance and international calls. Since the SPA3102 is designed for small businesses, it can also handle multiple phone calls simultaneously and allows the user to switch between lines while still maintaining constant Internet access. The built-in router also allows users to switch phone calls over to a standard telephone in case the Internet or electricity fails.

SVG1501 SURFboard Wireless Voice Gateway

The SVG1501 SURFboard Wireless Voice Gateway is a wireless voice gateway device that includes its own 4 cable ports, advanced firewall and security measures, the standard voice gateway telephone adapter that allows the user to connect a phone line to the device, and a wireless access point built directly into it. Motorola designed and distributed SURFboard. Private consumers as well as cable operators can use it to maintain a high-speed telephone and data transfer service. The device has a built in plug-and-play software, so the user only needs to turn it on and run the installation wizard on any computer to install it.

D-Link VoiceCenter 4-Port PSTN Gateway

The D-Link VoiceCenter 4-Port PSTN Gateway is a voice gateway designed for office buildings and allows up to 50 users to connect to the device simultaneously. Microsoft Response Point powers the VoiceCenter and comes with call forwarding, voicemail, voice-activated calling, and software to help setup and install the device. The VoiceCenter is made with portability and reliability in mind and can operate at temperatures between 32 and 122 degrees Fahrenheit as well as in humidity levels between 5% and 95%. The VoiceCenter is easy to use and easy to relocate. An entire office telephone network can be moved by simply taking the device to the new location and plugging it into the modem.

Future of VoIP Gateway Technology

VoIP gateway has become an efficient and flexible solution over the years and is used for office data and voice connectivity. Besides connectivity performance, VoIP is also more reliable under a variety of circumstances.

The future of VoIP gateway is very clear and precise. High-density, scalable, open platforms need to be designed and implemented to allow the millions of installed telephones and fast-growing number of H.323 computer clients (such as Netscape’s Communicator and Microsoft’s NetMeeting) to communicate over IP. Many vendors are in the process of designing interoperable VoIP gateways according to the latest architecture to meet service providers’ changing demands, corporate network clients, and individual carriers.
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piątek, 25 grudnia 2009

Voice over Internet Protocol

Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.

Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than the public switched telephone network (PSTN). The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression/translation of the signal into Internet protocol (IP) packets for transmission over the Internet; the process is reversed at the receiving end.[1]

VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream. Codec use is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.

History


VoIP technologies and implementations

Voice-over-IP has been implemented in various ways using both proprietary and open protocols and standards. Examples of technologies used to implement Voice over Internet Protocol include:

The Session Initiation Protocol has gained wide-spread VoIP market penetration, while H.323 deployments are increasingly limited to carrying existing long-haul network traffic.[citation needed]

A notable proprietary implementation is the Skype network. Other examples of specific implementations and a comparison between them are available in Comparison of VoIP software.

Adoption


Consumer market

Example of VoIP adapter setup in residential network

A major development starting in 2004[11] has been the introduction of mass-market VoIP services over broadband Internet access services, in which subscribers make and receive calls as they would over the PSTN. Full phone service VoIP phone companies provide inbound and outbound calling with Direct Inbound Dialing. Many offer unlimited domestic calling, and some to other countries as well, for a flat monthly fee as well as free calling between subscribers using the same provider.[12] These services have a wide variety of features which can be more or less similar to traditional POTS.

There are three common methods of connecting to VoIP service providers:

A typical analog telephone adapter (ATA) for connecting an analog phone to a VoIP provider
  • An Analog Telephone Adapter (ATA) may be connected between an IP network (such as a broadband connection) and an existing telephone jack in order to provide service nearly indistinguishable from PSTN providers on all the other telephone jacks in the residence. This type of service, which is fixed to one location, is generally offered by broadband Internet providers such as cable companies and telephone companies as a cheaper flat-rate traditional phone service.
  • Dedicated VoIP phones are phones that allow VoIP calls without the use of a computer. Instead they connect directly to the IP network (using technologies such as Wi-Fi or Ethernet). In order to connect to the PSTN they usually require service from a VoIP service provider; most people therefore will use them in conjunction with a paid service plan.
  • A softphone (also known as an Internet phone or Digital phone) is a piece of software that can be installed on a computer that allows VoIP calling without dedicated hardware.

PSTN and mobile network providers

It is becoming increasingly common for telecommunications providers to use VoIP telephony over dedicated and public IP networks to connect switching stations and to interconnect with other telephony network providers; this is often referred to as "IP backhaul".[13][14]

Many telecommunications companies are looking at the IP Multimedia Subsystem (IMS) which will merge Internet technologies with the mobile world, using a pure VoIP infrastructure. It will enable them to upgrade their existing systems while embracing Internet technologies such as the Web, email, instant messaging, presence, and video conferencing. It will also allow existing VoIP systems to interface with the conventional PSTN and mobile phone networks.

"Dual mode" telephone sets, which allow for the seamless handover between a cellular network and a Wi-Fi network, are expected to help VoIP become more popular.[15]

Phones such as the NEC N900iL, many of the Nokia Eseries and several other Wi-Fi enabled mobile phones have SIP clients built into the firmware. Such clients operate independently of the mobile phone network (however some operators choose to remove the client from subsidised handsets). Some operators such as Vodafone actively try to block VoIP traffic from their network.[16] Others, like T-Mobile, have refused to interconnect with VoIP-enabled networks as was seen in the legal case between T-Mobile and Truphone, which ultimately was settled in the UK High Court in favour of the VoIP carrier.[17]


Corporate use

Because of the bandwidth efficiency and low costs that VoIP technology can provide, businesses are gradually beginning to migrate from traditional copper-wire telephone systems to VoIP systems to reduce their monthly phone costs.[18]

VoIP solutions aimed at businesses have evolved into "unified communications" services that treat all communications—phone calls, faxes, voice mail, e-mail, Web conferences and more—as discrete units that can all be delivered via any means and to any handset, including cellphones. Two kinds of competitors are competing in this space: one set is focused on VoIP for medium to large enterprises, while another is targeting the small-to-medium business (SMB) market.[19]

VoIP runs both voice and data communications over a single network, which can significantly reduce infrastructure costs.[20]

The prices of extensions on VoIP are lower than for PBXs and key systems. VoIP switches run on commodity hardware, such as PCs or Linux systems. Rather than closed architectures, these devices rely on standard interfaces.[20]

VoIP devices have simple, intuitive user interfaces, so users can often make simple system configuration changes. Dual-mode cellphones enable users to continue their conversations as they move between an outside cellular service and an internal Wi-Fi network, so that it is no longer necessary to carry both a desktop phone and a cellphone. Maintenance becomes simpler as there are fewer devices to oversee.[20]

Skype, which originally marketed itself as a service among friends, has begun to cater to businesses, providing free-of-charge connection between any users on the Skype network and connecting to and from ordinary PSTN telephones for a charge.[21]

In the United States the Social Security Administration (SSA) is converting its field offices of 63,000 workers from traditional phone installations to a VoIP infrastructure carried over its existing data network.[22][23]

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środa, 28 listopada 2007

I often get asked "When did VoIP begin?" or "What is the history of VoIP?". Well, VoIP goes further back in time than most would expect - 9 years in fact. In fact, I did the first product review of a VoIP product back in 1996 within CTI Magazine (which later became Communication Solutions Magazine). CTI (Computer Telephony Integration) Magazine was at the forefront of news, articles, and reviews of anything to do with computers and telecom (or telephony if you prefer). In 1996 (aka 'ancient history'), CTI was best known for "screen pops", IVRs with database integration, but it also came to symbolize the convergence of the telecom and the datacom worlds. Most of this "CTI" technology was deployed first and foremost in the #1 industry that uses the telephone - namely the call center industry. Since CTI brings efficiencies to the call center, call centers were one of the first industries to deploy CTI. CTI Magazine was all about "convergence". It was perhaps a bit ahead of its time, since it predicted and preached "convergence", but alas, this magazine is now defunct, but not before spinning off the most successful VoIP magazine within the VoIP industry - Internet Telephony Magazine, which was launched in late 1997 with the first issue appearing in early 1998. So CTI Magazine certainly helped lay the foundation for convergence, which is certainly all the rage in any magazine or newspaper that you read now, including the New York Times, Newsweek, or the Wall Street Journal. Internet Telephony Magazine is now the torchbearer of VoIP and I could not be prouder than to write for this magazine.

Getting back to my history lesson, in 1996, I wrote the first product review of one of the true pioneers of VoIP - Vocaltec. I reviewed Vocaltec's Internet Phone product, which was perhaps the first "true" VoIP software application. It helped lay the groundwork to make VoIP mainstream. In fact, to my knowledge, Vocaltec's Internet Phone was the first VoIP product on the shelves of Compusa and other retail outlets. In re-reading my review, it reminded me of the old days of VoIP full-duplex issues/soundcard full-duplex driver issues. If you didn't have the latest sound card driver, you'd get a half-duplex CB/walkie-talkie type experience. In fact, the Internet hadn't really taken off at that point in history, so I had to use Compuserve of all things to download the latest sound card driver to get full-duplex VoIP sound. Ahhh, now those were the days... I miss BBSs (Bulletin Board Systems) as well.

If I may sidetrack for a moment, similar to MTV's "I Love the 80's", "I Love the 70's" shows, someone should have a retro-history technology equivalent for us tech geeks. Maybe if G4TechTV (formerly TechTV) is reading my blog, they can launch such a show. Anyway, here's a screenshot of my actual Vocaltec Internet Phone review. For nostalgia sake, click on the image below to read the review.

The history of VoIP had humble beginnings, but my oh my how far VoIP has come! But perhaps not far or FAST enough? Will future historians look back to 2005-2009 and say "If not for regulation barriers, telecom lobbyists, and government intervention, VoIP would have taken hold and exploded much faster"??? How future history will judge the 00's decade remains to be seen as the history of VoIP is is still unwritten...

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