Using a Broadband Internet Connection for an Extra Phone Line

This page is about setting up a UK ADSL connection to give me a second telephone service at my house. Using the Internet to make phone calls is sometimes called Voice Over Internet Protocol, but more often it's called VoIP.

I want to be able to use a "normal" telephone handset, and not have to use headphones, or have a computer turned on to use the phone. When I use the extra telephone I want it to seem like I just have a second line, and I want other people to be able to phone me just like I had a second line installed.

Why Not Just Get a Second Line Installed Then?

I don't want the man from BT to drill another hole in the side of my house. As well as that:

VoIP services provide more features

VoIP services are both more flexible and typically provide more features than a new fixed telephone line:

VoIP is cheaper

VoIP makes better use of the single line that I already pay for. Because I already have a broadband internet connection, and pay my monthly subscription for that, the extra costs for a VoIP service are small.

What's Not So Good About VoIP?

How Much Bandwidth is Needed?

At the highest quality standard, just under 100kbps is required for one extra line -- but only while it is being used! In the UK, standard ADSL is limited to upload speeds of 256kbps, so you could use two extra lines at the same time on a stanard ADSL connection.

You can set your VoIP phone to lower the call quality, and to use silence suppression, which both save bandwidth.

Is all VoIP the Same?

No. Using VoIP means that you are sending your voice over the internet, and there are several ways to do this. The Internet standard called SIP is the one that is most widely supported for using the internet like a traditional telephone network, but there are others.

A competing VoIP implementation is called Skype. Advantages of the Skype service include:

Disadvantages of Skype are:

I have decided not to use Skype, and will set up SIP-based VoIP.

How Does Calling a Normal Telephone From the Internet Work?

Although calls between two VoIP phones only need to use the Internet, calls to a normal telephone number have to use a VoIP service provider. The service provider will connect your VoIP call from the internet to the telephone network, and usually make a per-minute charge for this.

Your service provider can also supply a telephone number so that normal telephones can call your VoIP phone, and they may charge a subscription for providing the number.

What About Free phone Calls?

There is currently no extra charge for calls to other VoIP phone users. Maybe when VoIP phones become popular the phone companies that run the Internet will start prioritising their own data on the network, and the "free" voice call quality will drop unacceptably? ISPs are already encouraging their customers to move to products where they pay for the amount of data that they send over the internet, rather than paying a flat rate each month. Hopefully these per-packet charges will be lower than the per-minute phone charges that we've been trying to avoid!

Even when calling between two VoIP phones it is often useful to have a service provider help the two VoIP phones connect to each other. Many home and business internet connections use a NAT router to allow several computers to share the single internet connetion, and this can stop SIP working unless a service provider helps set up the connection. A technique called STUN is often used to help two VoIP phones connect to each other. If you don't have a service provider there are free public servers on the internet that you can use.

What Service Providers Are There?

There are lots of service providers, and some variation between the services that they offer, so it's worth comparing several to see what is available.

BT offer several different VoIP packages, and gadgety hardware to go with them.

Comparison of the VoIP Services I'm Using

DrayTel Sipgate VoIPFone
Mobile Calling14p/min (standard tariff)
10-5p/min (silver tariff)
9.9p/min
Geographic Number Free (after £10 credit added) Free £1.99/month
Fax to Email Number Cheapest options is currently £4.99 for an 0870 fax number, and you lose the number if it is not used for 90 days. Free 05600 number (national rates, not accessible from all phone networks), or free 0870 number (national rates).
Send SMS NoneOut from web, 5.9p, replies to own mobile number Out from web, replies to own mobile, or to VoIPFone account
Call Chargesper secondper minuteper second
Monthly Charges None None £6.98 for 500 landline calling minutes and geographic number
Conference Calling Invitees can call in to an 0870 number. No other fees.
Comments Poorest web interface - must login several times per session Best web site and control panel Web site is Flash app and AJAX. Too much of both.

What Hardware or Software Can I Use?

You don't need to use a telephone handset with VoIP -- you can use a microphone headset with a computer, or at a pinch even the built in microphone and speakers. I want to be able to make calls using a traditional telephone though; my options include:

A router with built in VoIP ports

This is the most straight-forward option. By getting a router with an ADSL modem and VoIP ATA built in I can simply plug a telephone handset directly in to it. There should be no problems with NAT or any built in firewall because the VoIP functions are all part of the same device.

I'm getting a Draytek Vigor 2800V. This is costing me £165 from Data Comms Direct, which is expensive for an ADSL router, and the version with a wireless access point built in costs even more. (See www.draytek.co.uk/products/router_compare.shtml) The 2800 series supercede the very similar 2600 series by including ADSL2/2+ support, but the Draytek support forum suggests that the ADSL2+ support is not complete (download speed limited to 8 Mbps, not 24 Mbps). Maybe future firmware will fix this, but luckily (?) BT only provide ADSL 1 services at the moment.

Only the models with V in the model name have VoIP ports built in.

A cheaper option is an ADSL router with a single VoIP port at £46 from Dabs.

I'm paying for the expensive router because it has a built in VPN server, support for ADSL2/2+, and some advanced firewall options. These aren't things that most people would need or use.

A VoIP adaptor with your normal telephone

An Analogue Telephone Adaptor (ATA) can plug in to your network, and use your Internet connection to make phone calls. You simply plug your telephone in to it, and make calls as normal. Cheaper ATAs may be restricted for use only with the service provider that supplied them. It might be important to change the Internet gateway configuration to allow VoIP calls to be made and received.

A good range of DECT phones. www.home-phones.co.uk/asp/default.asp

A phone that can handle two lines at the same time: www.home-phones.co.uk/asp/product.asp?product=258

2-line DECT phones exist, but are very expensive. Search for "BT Airway DECT" on eBay.

A VoIP phone

A VoIP phone plugs straight in to an RJ45 network socket and registers itself with the VoIP service. There are also wireless VoIP phones that use a wireless network connection. VoIP phones are more expensive than tradional telephone handsets.

Computer Software

You could use your computer as a VoIP telephone. It doesn't matter what software you use if it is SIP compliant it will interoperate with any other SIP compatible software. X-ten produce a free version of their software for Windows, Linux and Apple, called X-lite. Some VoIP providers will supply this to you preconfigured with your account details (SIP Gate do this), otherwise you can download it from CounterPath.

X-Lite is a free download, or eyeBeam is the more featureful pay-for version.
www.xten.com/index.php?menu=products&smenu=xlite&ssmenu=download

Miscellaneous Cables and Adaptors

VoIP hardware will always have an RJ45 connection, and a standard network cable will be needed for that. If the hardware doesn't have the "standard" BT connector sockets, then there should be adaptors provided in the box.

So Why Not Give Up The Original BT Line, and Just Use VoIP?

I need to keep the BT line to have my ADSL internet connection.