VoIP Phone Numbers For Mobile Users - Birchills Blog
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VoIP Numbers For Mobile Users

Ball bearings illustrate the concept of VoIP Phone numbers for mobile users
A mobile phone service behaves in many ways which are different to how a VoIP phone service works. One of the major differences is how phone numbers are allocated and work. Understanding the differences allows you to get the most from your VoIP service and avoid costly mistakes.


There are broadly 3 types of telephone services for business available in the UK
1)     Mobile
2)     Landline
3)     VoIP – Voice Over The Internet (Protocol)

In order to keep this piece relatively simple I will discuss the similarities and contrasts between mobile and VoIP.
With mobiles you buy or rent a SIM card which you then plug into your device. Crucially the SIM contains the mobile phone number. The mobile number will always start with 07. When mobile services began you could tell who the mobile provider was by the first few digits of the phone number. This no longer applies with number portability.
This means that for a mobile service to work it needs a SIM and you need to have entered some kind of payment arrangement with your mobile service provider.
Because SIM’s can only can provide one phone number some phone manufacturers have allowed you to be able to install 2 SIM’s in your phone so you get 2 phone numbers. Vodafone and BT have introduced hybrid services which allow you to connect landline numbers to your phone so that you can receive calls on your mobile but not dial out.
When dialling out from a mobile your choice is limited to announcing the number from which you are calling or withholding it.

If you want to transfer your mobile phone number to a different provider then you need to request a a PAC from your existing provider. It must be issued to you immediately over the phone or within two hours by text message.
Ofcom provide the following guidance;-
“Your PAC is likely to be a nine digit code and is valid for 30 days. If it runs out, you will need to request a new PAC from your existing mobile provider.
You should then contact your new mobile provider and give them your PAC.
Once your new provider has your PAC and notifies your existing provider of the port request, your number will normally be transferred the next working day.
Some mobile phone providers may charge you a fee to move your number. You must also remember that, if you are still under contract to your old company, you may still be liable for charges under that contract.”
You cannot transfer the number to a landline or VoIP provider.

A VoIP service, such as the Birchills service, uses landline phone numbers as part of the service. These numbers can be any number except for mobile numbers, so they can start with 01, 02, 03 etc. The numbers available vary by VoIP provider and several providers may be able to provide the same number. It is possible to have numbers outside the UK
A VoIP service brings together the functions of a telephone switchboard, which used to be called a PBX, connections into the worldwide landline phone network and telephone numbers to provide the service. The provider may also provide special VoIP phones (also called IP phones) from specialist manufacturers.  The phones are configured to be extensions of the switchboard and are numbered separately – so an extension may have a numbers like  101, 102 etc.
The VoIP service for one customer can have multiple phone numbers associated with it. This means that you can answer inbound calls made to any phone numbers you have  You can also make calls from any phone number associated with your account. This is all set up either using an online portal or control panel or by the VoIP provider. You can add or remove phone numbers at will. Depending on your provider there may be a charge for additional phone numbers or in the case of Birchills Telecom they are free (with one per extension).
You pay a subscription to the service for the switchboard functionality-( including all of the features such as IVR, call recording)  and the connections to the telephone network.


If you want to transfer your landline phone number to a different provider then you need to request  your new provider to liaise with your existing provider.  This is called porting a number The new provider will send you a form and you will need to provide evidence that you have the number currently.
To enable porting to happen the various companies need to have an overall porting agreement. Not all providers are party to this and some transfers cannot be done. BT and all of the large provider fortunately are in the agreement. The losing provider defines the timescales on which ports happen and that varies from a few days to weeks.
If the form is completed correctly then the transfer will proceed.  The telephone line on which the number is located will cease to function when the transfer happens – if you have broadband on that line it will cease.
Handling the management of the port is crucial if your service is to be maintained. You will need a working service from your new provider to allow the port to proceed.


A mobile phone services is a personal phone service which will only operate with a phone number attached to a SIM
A VoIP phone service is a business phone service based around a network. Phone numbers can be added or deleted at will.

Green Dragon 21/5/2016
Thanks for the really useful info, I passed this onto a colleague who couldn't understand why he had to pay for a service in advance of a number port. He seemed happy
Best wishes

Paula 30/05/2016


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