Some VoIP services may only allow you to call other people using the same service, but others may allow you to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. VoIP services convert your voice into a digital signal that travels over the Internet. If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination.
VoIP can allow you to make a call directly from a computer, a special VoIP phone, or a traditional phone connected to a special adapter. In addition, wireless "hot spots" in locations such as airports, parks, and cafes allow you to connect to the Internet and may enable you to use VoIP service wirelessly. A broadband high speed Internet connection is required.
This can be through a cable modem, or high speed services such as DSL or a local area network. A computer, adaptor, or specialized phone is required. If you use your computer, you will need some software and an inexpensive microphone. Special VoIP phones plug directly into your broadband connection and operate largely like a traditional telephone. If you use a telephone with a VoIP adapter, you'll be able to dial just as you always have, and the service provider may also provide a dial tone.
Let's face it -- few people really panic when their e-mail goes down for 30 minutes. It's expected from time to time. On the other hand, a half hour of no dial tone can easily send people into a panic. So what the PSTN may lack in efficiency it more than makes up for in reliability. But the network that makes up the Internet is far more complex and therefore functions within a far greater margin of error.
What this all adds up to is one of the major flaws in VoIP: reliability. One of the hurdles that was overcome some time ago was the conversion of the analog audio signal your phone receives into packets of data. How it is that analog audio is turned into packets for VoIP transmission? The answer is codecs. A codec, which stands for coder-decoder , converts an audio signal into compressed digital form for transmission and then back into an uncompressed audio signal for replay.
It's the essence of VoIP. Codecs accomplish the conversion by sampling the audio signal several thousand times per second. For instance, a G. It converts each tiny sample into digitized data and compresses it for transmission.
When the 64, samples are reassembled, the pieces of audio missing between each sample are so small that to the human ear, it sounds like one continuous second of audio signal.
There are different sampling rates in VoIP depending on the codec being used:. Codecs use advanced algorithms to help sample, sort, compress and packetize audio data. The codec works with the algorithm to convert and sort everything out, but it's not any good without knowing where to send the data. In VoIP, that task is handled by soft switches. This is the numbering system that phone networks use to know where to route a call based on the dialed numbers. A phone number is like an address:. The switches use "" to route the phone call to the area code's region.
The "" prefix sends the call to a central office, and the network routes the call using the last four digits, which are associated with a specific location. Based on that system, no matter where you're in the world, the number combination " " always puts you in the same central office, which has a switch that knows which phone is associated with " They look for IP addresses, which look like this:. IP addresses correspond to a particular device on the network like a computer, a router, a switch, a gateway or a telephone.
However, IP addresses are not always static. They're assigned by a DHCP server on the network and change with each new connection. This mapping process is handled by a central call processor running a soft switch.
Think of the user and the phone or computer as one package -- man and machine. That package is called the endpoint. The soft switch connects endpoints. The soft switch contains a database of users and phone numbers. If it doesn't have the information it needs, it hands off the request downstream to other soft switches until it finds one that can answer the request.
Once it finds the user, it locates the current IP address of the device associated with that user in a similar series of requests. It sends back all the relevant information to the softphone or IP phone, allowing the exchange of data between the two endpoints. Soft switches work in tandem with network devices to make VoIP possible.
For all these devices to work together, they must communicate in the same way. This communication is one of the most important aspects that will have to be refined for VoIP to take off. As we've seen, on each end of a VoIP call we can have any combination of an analog, soft or IP phone as acting as a user interface, ATAs or client software working with a codec to handle the digital-to-analog conversion, and soft switches mapping the calls.
How do you get all of these completely different pieces of hardware and software to communicate efficiently to pull all of this off?
The answer is protocols. There are several protocols currently used for VoIP. These protocols define ways in which devices like codecs connect to each other and to the network using VoIP. They also include specifications for audio codecs. The most widely used protocol is H. It provides specifications for real-time, interactive videoconferencing, data sharing and audio applications such as VoIP.
Actually a suite of protocols, H. As you can see, H. That's what allows it to be used for so many applications. The problem with H. An alternative to H. Smaller and more efficient than H. MGCP is geared toward features like call waiting.
You can learn more about the architecture of these protocols at Protocols. One of the challenges facing the worldwide use of VoIP is that these three protocols are not always compatible. VoIP calls going between several networks may run into a snag if they hit conflicting protocols. Since VoIP is a relatively new technology, this compatibility issue will continue to be a problem until a governing body creates a standard universal protocol for VoIP.
VoIP is a vast improvement over the current phone system in efficiency, cost and flexibility. Like any emerging technology, VoIP has some challenges to overcome, but it's clear that developers will keep refining this technology until it eventually replaces the current phone system. The central call processor is a piece of hardware that runs the soft switch. VoIP has its distinct advantages and disadvantages.
The greatest advantage of VoIP is price and the greatest disadvantage is call quality. For businesses who deploy VoIP phone networks -- particularly those who operate busy call centers customer service, tech support, telemarketing, et cetera -- call quality issues are both inevitable and unacceptable.
To analyze and fix call quality issues, most of these businesses use a technique called VoIP call monitoring. VoIP call monitoring, also known as quality monitoring QM , uses hardware and software solutions to test, analyze and rate the overall quality of calls made over a VoIP phone network [source: ManageEngine ]. Call monitoring is a key component of a business's overall quality of service QoS plan.
Call monitoring hardware and software uses various mathematical algorithms to measure the quality of a VoIP call and generate a score. The most common score is called the mean opinion score MOS. The MOS is measured on a scale of one to five, although 4. An MOS of 3. To come up with the MOS, call monitoring hardware and software analyzes several different call quality parameters, the most common being:. There are two different types of call monitoring: active and passive.
Active or subjective call monitoring happens before a company deploys its VoIP network. Active monitoring is often done by equipment manufacturers and network specialists who use a company's VoIP network exclusively for testing purposes [source: VoIP Troubleshooter. Active testing can't occur once a VoIP network is deployed and employees are already using the system.
Passive call monitoring can detect network traffic problems, buffer overloads and other glitches that network administrators can fix in network down time. Another method for call monitoring is recording VoIP phone calls for later analysis. This type of analysis is limited, however, to what can be heard during the call, not what's happening on the actual network.
This type of monitoring is usually done by human beings, not computers, and is called quality assurance. VoIP solutions aimed at businesses have evolved into unified communications services that treat all communications—phone calls, faxes, voice mail, email, web conferences, and more—as discrete units that can all be delivered via any means and to any handset, including cell phones.
Switching to VoIP might also help you save money on communications services. Long-distance and international calls are generally free with VoIP service. The only charge is for your internet access. The best VoIP providers implement IP telephony in a manner that protects your investment in existing telephone equipment, even if you have analog telephone stations. This site uses cookies and other tracking technologies. These help the site function better. They also help us improve it.
This data gives us feedback on how you use our products and services, helps us develop promotional and marketing material more relevant to you, and allows us to connect you with apt content from third parties. Some broadband and home phone providers offer VoIP as part of their services so that they may do things a little differently. It's the standard form of the phone line from a number of FTTP fibre-to-the-premises providers, for example, and VoIP is available as part of almost any business broadband or phone package.
Either way, your provider will give you all the info you need. Traditional telephony, known as the Public Switched Telephone Network or PSTN for short, works through physical phone lines, cable systems and networks and allows users to make landline and cellular telephone calls. IP telephony, however, is much more versatile and enables voice, data, and video to be transmitted to a variety of devices including smartphones, laptops, tablets and IP phones at a much lower cost.
There are a variety of applications and software communications systems that utilize Voice over IP to offer full-featured business communications solutions as well as internet telephony for personal use. Examples of such products include 3CX, which offers a company communications system integrating voice, video, chat and more. Most modern device manufacturers, like Apple, have integrated native IP apps into there smartphones, such as Apple FaceTime which provides call and video functionality.
VoIP technology enables traditional telephony services to operate over computer networks using packet-switched protocols. Packet-switched VoIP puts voice signals into packets, similar to an electronic envelope. Because VoIP uses packets, much more information can be carried over the network to support and enhance your communication needs. In addition to traditional voice services, VoIP gives you access to advanced applications that can potentially help your staff be more agile and productive.
VoIP solutions aimed at businesses have evolved into unified communications services that treat all communications-phone calls, faxes, voice mail, email, web conferences, and more-as discrete units that can all be delivered via any means and to any handset, including cell phones.
VoIP phones make and receive calls via the Internet. This means that they can use your office's Internet connection to connect to the telephone network. In other words, if your office is already wired for Ethernet, you do not need to invest in additional copper wiring to use your business phones. In order to make phone calls, you will first have to register your VoIP phone to your account. This is the process of connecting your phone to your service provider so that they can communicate with each other.
The whole process of registering a phone will take you, or your IT staff, less than 30 minutes. Plus, there's no need to call the local phone company. Phones are active as soon as they're registered-no red tape. Outwardly, you might not even tell the difference between a VoIP phone and another business desk phone. VoIP phones tend to have handsets, receivers, speaker locations, and button placements that make them physically indistinguishable from the business phones you currently employ.
VoIP phones use the same keypad as landline phones. The keypad comes with nine numbers, zero, and corresponding letters that enable alphanumeric input. If you've ever used a phone before, you've seen this keypad. VoIP phones generally have dedicated buttons for redial, transfer, conference, hold, mute, voicemail, and speakerphone.
These buttons are set along the side of the number pad. VoIP phones and other business phones use these features almost universally. HD Voice offers at least twice the audio range of landline phone service. The spread for landline voice quality is 3. In other words, the quality of your calls will be much higher using two VoIP phones than two traditional phones. This reduces clutter on your desk and simplifies inventory management. It can also save you money, as power adapters are often sold separately from the phones.
VoIP phones handle calls differently than other business phones. Above, the buttons in the yellow rectangle are the toggle buttons. VoIP phones allow you to pick between current, incoming and held calls using the toggle buttons.
0コメント