One key advantage is that my chosen solution makes use of a telephone handset that looks and works like a standard telephone. As you can see from the picture below it really is just like any other telephone.

This telephone, like the majority of VoIP telephones, uses the open standard Session Initiation Protocol (SIP) to allow it to make and receive calls over an Internet connection. SIP telephony is very popular with businesses and has been in use for many years. It was designed in 1996 and became an Internet standard in 1999. What makes SIP different to other telephony standards is that it was developed by the Internet industry and not the telecommunications industry and was designed from day one to use the Internet to make and receive calls.

The standard telephone system here in the UK, and around the world, is called a Public Switched Telephone Network (PSTN) that uses an analogue connection and copper wires between the handset and the local telephone exchange. This is incompatible with a digital system like VoIP so you need to use something called an Internet Telephony Service Provider (ITSP), sometimes called a VoIP Service provider.

The job of an ITSP is to provide a gateway between a SIP based service and the PSTN services so that anyone on the PSTN can call someone using a SIP service and vice versa. You can call my business number from any land line or mobile phone and I can call your telephone or mobile phone in exactly the same way.

Telephone Numbers and VoIP

Another important service provided by an ITSP is to provide a standard telephone number available to the SIP service so anyone with a VoIP telephone using SIP can have a number. My business number, 01822 678203, is provided by one of my ITSP's. It looks exactly like any other Tavistock number and anyone calling it gets exactly the same experience as they would if they called any other Tavistock number.

Any UK telephone number starting with 01 or 02 are arranged geographically, with a specific area code for each part of the country. As an example 01822 indicates that the area served is Tavistock and 01904 is the area code for York. In theory ou should be able to identify the area served just by looking at the area code.

A mobile telephone has no specific geographic location so their numbers begin with 07 to indicate this to the caller. Numbers starting with 070 are special 'personal numbers'. These are numbers allocated to an individual or business, who can use them to redirect incoming calls to any phone they wish, as and when they choose.

Some years ago OFCOM created 056 numbers for 'location independent electronic communication services', such as VoIP as a VoIP telephone has no geographic area and can be operated in any location that has an Internet location. Since 2005 VoIP services have been able to provide standard area code numbers allocated to them and most VoIP users prefer them. Charges for calling 056 numbers can be higher than for calling 01 or 02 numbers helping to make 056 numbers less attractive.

It is possible to allocate a standard 01 or 02 number to a VoIP service regardless of the location of the VoIP telephone or user. So someone living in Penzance could opt to have an 020 7 London number on their VoIP service just as easily as having the 01736 Penzance area code. This has meant that recognising the geographic area for a telephone number is now much less reliable as it could easily be a VoIP based service located anywhere in the world.

You can find much more information about UK telephone numbers here.

http://www.area-codes.org.uk/

Have Number – Can Travel

Because a VoIP telephone connects to the Internet and not to a telephone line it can be used anywhere that has an Internet connection. For example I took my telephone with me when on holiday in France. I could make and receive calls to my normal office number in exactly the same way as I can when at home. It meant any customer calling me paid exactly the same call charges they would always pay and nobody had to know that I was not in the UK.

Criminals have recognised this key ability of VoIP telephony and have used it to fool callers into thinking they are calling a number at a specific location. I have seen this done with London numbers even though the criminals are based in another continent. Because of VoIP you can never assume that the person you are calling, even when it's a standard 01 or 02 number, is in the area designated by the dialling code.

What You Need to Know

VoIP services, and especially those based on SIP are extremely useful and are almost certainly the future of telephony.

However, like all technology, and especially any that uses the Internet, there are a few things that you need to be aware of before you decide to use the service.

VoIP can offer much better call quality than you can get with an ordinary land line. This is because a VoIP call is not limited to the low bandwidth used by a standard telephone line. In practice this may or may not be useful as it will depend upon who you are calling and what equipment they use.

An Internet connection will never be as reliable as a standard telephone line simply because it is based on more technology and more connections. If your Internet connection fails then you have no telephone service. This may or may not be a big issue but even the most reliable Internet connections will have some down-time.

A standard telephone line should achieve 99.999% uptime, the legendary five nines reliability standard that the telecommunications world strives to achieve. This equates to no more than five minutes with no dial tone per year. I am yet to come across any Internet connection that can boast such a high level of reliability. Many would struggle to achieve 99.9% or around eight hours of downtime per year.

The quality of any calls will also be dependent upon the Internet connection having enough bandwidth for the call. As a rule of thumb the bandwidth required is 1.5 times the bandwidth used by the CODEC that determines the call quality. The highest bandwidth CODECS will typically use 64,000 bits per second (64Kbits/s) so the available bandwidth needs to be at least 96 Kbs.

For almost any Internet connection that is a small amount so you might think that your calls will be fine. The trouble is that the Internet Protocol (IP), usually version 4 has no standard Quality of Service (QoS) built in and that means that data packets can be delayed or lost. Whilst that is fine for things like email or web browsing it is much more noticeable on a voice call.

The usual solution is to make sure that the Internet connection always has some spare bandwidth and for some this will usually be all that is required. In other cases if the Internet connection is heavily used then some form of QoS must be used to ensure that any voice calls always have some reserved bandwidth. Things should improve greatly as IP version 6 is rolled out as this has some QoS support built into the standard.

If you have enough spare bandwidth then you will be able to support more than one VoIP 'line' and even have more than one number.

A Low Cost Second Line

If you already have a reasonable Internet connection and you could benefit from having another telephone 'line' then you really should consider using a VoIP based service. I have used it for my business since 2011 and I would not go back to a traditional telephone service. Select the right SIP provider and you can even get an 01 or 02 number for free. The SIP based handsets are not expensive either. You can get a basic Grandstream handset for about £35 including VAT.

You can also use a VoIP client on a mobile telephone so you can make and receive calls using your mobile but without using your mobile telephone number. I can answer calls to my office number from my mobile without having to do any call redirection. I can also make calls from my mobile and they will appear to the caller to be coming from my office number.

If you choose to make and receive calls on a mobile telephone then I recommend that you use a low rate CODEC as 3G and 4G connections don't have as much available bandwidth as you might expect. This also has the benefit of reducing the amount of data you will use per call and it should make mobile SIP calls more reliable.

If you want to look at some handsets take a look at the Soho66 site here.

http://soho66.co.uk/7020/all/1/Business-VoIP-Phones.aspx

There are plenty of VoIP handsets to choose from and you can easily find them with a simple web search. In my experience it is best to select a make of handset that is supported by the ITSP you choose. Select your service provider first and then see what handsets they support or have configuration information for. It really will make setting things up quicker and easier than trying to figure out the settings yourself.

If you are interested in using a VoIP service please call or email me and I will be happy to help you.