Making calls over the Internet

Did you want a local number in the UK that you could use to make and receive calls over the Internet? Call plans are a lot cheaper, especially if they are made internationally.

I will be talking about the industry standard system of Voice over IP, which is called SIP, rather than proprietary systems like Skype or Vonage.


Session Initiation Protocol or SIP is the industry standard way to deliver calls over the Internet. A SIP channel is the VoIP version of a telephone line. Each SIP channel has it’s own account.

Direct SIP to SIP calls are free, but not that practical. A SIP provider usually offers a telephone number that customers can call you on. Some SOHO (Small Office/Home Office) providers may offer a local number for free, others charge an annual fee for this service.

SIP providers can offer extra services such as call plans that reduce the cost of outgoing calls, as well as providing paid add-ons at their end like premium voice mail and call waiting as well as virtual receptionist (known as IVR or Interactive Voice Response) however, these services can prove costly and it may be cheaper to use a cloud PBX solution, or host your own on a PC or even a Raspberry Pi.  I will cover these next.

Using your own IP PBX

Using your own IP PBX(Public Branch Exchange) makes it cheaper to manage calls in house if you are running a business that needs a phone system.

Asterisk PBX is an Open Source project to create a fully functional PBX which was developed in 1999 by a company called Digium which were bought up by Sangoma. FreePBX adds an easy interface to Asterisk PBX.

  • Cloud based PBX such as OPL for £30+VAT per month for 10-15 concurrent calls.
  • Pre-built appliance like the Sangoma PBXACT UCS-0025 for around £558 that handles 25 phones and 15 simultaneous calls.
  • Build your own FreePBX system with a PC or a Raspberry Pi.

Next, you enter your SIP provider details and then configure your SIP phones.

SIP Phones

Desktop phones

DECT Cordless


Just as you would with a normal desk phone, you can make and receive calls, as well as making calls within an office. If you have your own IP PBX solution, internal calls will not affect your broadband connection. A single line desktop IP phone starts from about £40.

DECT base stations can handle up to 8 DECT phones and up to 8 VoIP accounts. You can use range extenders to improve the coverage area around your office and over multiple floors. A DECT system starts from around £100 including the base station and £55 per handset.

Apps such as Zoiper allow you to make and receive calls anywhere there is an Internet connection, so you can configure it to use your SIP provider or your own PBX. The app works for Windows, Mac, Android and iOS devices and is free for non commercial use, otherwise its £60 one off price.

SIP Providers

SIPGate Basic

SIPGate provide SIP accounts for domestic and SOHO users. You get to choose a local number for free and you can buy a cheap call bundle for £9.95 per month that gives you UK calls, they do other bundles for EU calls and offer cheap rates for overseas countries like 1.90p per minute to the USA.

SIPGate Trunking

SIPGate Trunking starts at £5+VAT per month for a 1 concurrent call in and 100 concurrent calls out.


SIPStation offers trunking solutions that start off at £12+VAT per trunk.

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