Wednesday, October 20, 2010

As the quality of VoIP calls can improve

In these days when you're just starting a home or small office, the chances that you also consider VoIP providers, rather than proposing a different phone line, but the analog VoIP call quality and reliability depends on a number of factors off. Here are some suggestions for improving the quality of VoIP calls.

There is a glossary at the end of this article.

Choose the right combination

If you use an IP phone or analog telephone adapter, make sure you choose a with proven experience. There are so many manufacturers and new entrants to the market each month can be a difficult task to remove the bullet. Many manufacturers ship their new handsets with pre-release firmware, can give rise to within a range of topics, ranging from the difficulties in configuration, to, and calls sound choppy. A Web site is for the monitoring of good advice for users of mobile phones and ATA's community site provides a wealth of information about VoIP in general.

Select the codec

A codec (short for encoder / decoder) is the software algorithm is used to convert analog audio to a speech (usually compressed) in digital form. There are a number of codecs for VoIP. Most ATA devices and at least two.

In general, the compromise in the choice of a codec between the bandwidth and CPU utilization. The codec is the bandwidth costs usually requires little CPU power. Select the codec that is used depends on you, especially if you are) to a telephone system to connect your local network (usually the case in large offices, or, as so often come with a small office or home, in touch to a virtual PBX provider or Internet telephony, broadband services. If you are connected to the network bandwidth limitations, so you must choose a full-rate codec such as G711. When you connect to the Internet, but you obviously need to have some compression. In this case, a codec such as G729 or iLBC give good results.

Since the Internet is an open network uncontrolled, travel information about them is often a path deviations disorderly increases. Data packets do not often come in order, and with various delays (VoIP jargon jitter). Some much better than other codecs with jitter, for example, G729 is particularly resistant to jitter. In some cases, the packets are lost. Virtually all VoIP codecs react badly to the loss of packets.

If you have a large compression codec, which necessarily requires more CPU power, it is important to ensure that they are) installed on a robust phone with the latest firmware to see (note above regarding the choice of connection. Badly written firmware often causes disturbed audio compression with a high level because the CPU is not easy to cope with the requirements of the algorithm.

Prioritization of Internet traffic

Select a good unit and the codec is the most appropriate of no use when VoIP calls are to compete with other Internet traffic on your broadband connection. It could be a perfect crystal with a customer when they suddenly interrupted by all sorts of distortions and dropouts, because the computer is busy downloading several megabytes of e-mail.

Most SOHO routers have a modern system of priorities for different types of traffic competing for the use of the connection. The simplest form of giving more importance, the visitors destined to a specific IP address and port number or range. You need the IP address and UDP port to define the field for your audio VoIP providers (they will be able to) make this information available. Another simple form of hierarchy and internal IP address - but this requires that your phone a static IP address (rather than automatically assigned to a library) of your router.

Some modern routers are intelligent enough to recognize VoIP traffic and prioritize that traffic than others. In fact, some manufacturers are now made with cheap equipment between the router and broadband modem connection to connect. These devices require no installation and commissioning automatically prioritize voice traffic.

However, other routers offer, which is such as QoS (Quality of Service) known. These are special tags that the IP packets to read from some ISP routers and are used in order to prioritize the traffic within the ISP network to be assigned (even left a broadband modem). Most ISPs also provide broadband telephony services are a kind of QoS support. It is best to consult the technical service for ISPs exactly how. While valuable, QoS will not help if you have already paid for the priority of the internal data traffic with the methods described above.