Common Questions Associated With VoIP

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Having been immensley popular, the emergence of VoIP has proved to be a great new communication tool with many advantages over traditional phone calling. The rapid expansion of this new technology has also inevitably led to various associated problems, some of which have been answered here!

How does VoIP work?

Computers take samples of sounds via microphones at a very high rate (8,000 times per second or more). These recorded samples are not stored locally, but are sent over the network to another computer and played there, so that the receiver can hear them.
Computers often compress the sound samples so as to occupy less space. Limited frequency ranges are used. CODEC's (compressor/ de-compressor) are algorithms that enable audio to be compressed. A huge variety of CODEC's exist for all sorts of applications (e.g. sound recordings or movies). VoIP CODEC's are fine tuned to work well for compressing voice. Bandwidths only include those sound frequencies associated with human voices.
So, when the sounds are recorded in the computer, then compressed to tiny samples, these are then aggregated into larger chunks/ collections and placed into data packets (known as 'packetization'). Data packets are able to be transmitted all over the IP network. Typically, single IP packets have 10,000 milliseconds+ of audio.
Sometimes packets get lost. In this case packet-loss concealment (PLC) can take place. PLC involves filling in the sound gaps with noise acceptable to the human ear. Forward-error connection (FEC) fills in the gaps with then mathematically modified neighboring past packets. A kind of rough packet reconstruction.
Occasionally packets are delayed, especially bad when using VoIP since packets that are too old are discarded. PLC tends to smooth the audio out in such circumstances.
Variation in packet delay is called 'jitter'. Jitter makes voices sound glitchy, it is combated with specific jitter buffer algorithms. What effectively happens here is packets are queued to reduce the number discarded, late or delayed.
An agreed protocol exists to allow computers to find each other and exchange information. Agreed contents formats (termed 'payload format') exist for the packets.

Is a computer necessary in order to use VoIP?

A computer isn't required when using VoIP services centered around mobile phones. Adapters, which are often supplied by mobile phone VoIP providers, connect phones to the high-speed connections of the internet. Computers are able to be used to allow improved management of various features available from the provider, although this is not necessary.

What is the relation of computer software use in conjunction with VoIP?

Computer-to-computer calls are the easiest and cheapest of the VoIP calling methods. Calling plans are not required since this type of call is totally free. All that is required is the free software from the internet, a reasonable connection with the internet, speakers, a microphone and a sound card. Apart from the bill for the use of the monthly internet service no other call charges exist, regardless of call number.

Is it possible to mix hardware from different VoIP providers?

Typically the major providers of VoIP (AT&T, Verizon Voicewing and Vonage) "lock" their hardware, ensuring it only works with their own particular services. In some deals the service providers end up leasing the equipment to you and are able to refund a certain degree or all of, the set-up fee when you decide to terminate the service with them. Alternatively, you can buy all the hardware required from a retail store, which can then be used on any VoIP service.
Services that promote VoIP for running on your computer, e.g. Yahoo Messenger and Skype, don't need any specific hardware. Many of these VoIP services can be run from the exact same machine, albeit not at the same moment in time.

I have ADSL. What should my internet connection speed be to allow VoIP?

Generally you should have a 512/128 connection speed or higher.

What are the advantages to using VoIP over conventional phone calling?

By far and away the greatest benefit to using VoIP services is that they tend to be cheaper than traditional phone services. In some circumstances they are even free. Additionally, not too much equipment is required and upgrades that are eventually necessary are typically done with no new physical equipment, only simple and easy to use software downloads. Many more features tend to be possible for VoIP, this being due to the ease with which information is transported about via the internet.

What is the quality of VoIP calls like?

In most instances the quality appears to be very good. Small problems sometimes occur then there is an excess of incoming and outgoing internet traffic along the phone lines. Poor quality on the phone lines can be improved through paying to increase the connection speed or prioritizing phone traffic through your network via setting up the 'Quality of Service' option.