Our SIP2SIM service is a SIM or eSIM that allows a real mobile phone to connect to your own SIP/VoIP server or to our own VoIP service. With roaming in the EU and US and an option to include data.
Link SIP2SIM to a VoIP service
SIP2SIM is just a SIM or eSIM. You then combine this with your own SIP server, a third party SIP service or a VoIP Numbers from A&A to create an end to end voice service.
SIP2SIM, to a SIP Server
If you run your own SIP server, or have a 3rd party VoIP service, the SIM/eSIM can be configured to register to it, just like any of your other extensions.
SIP2SIM, to an A&A VoIP Number
You can order a UK number from us, and set that up to be linked to the SIM/eSIM. Our normal features such as call recording, voicemail to email etc can then be used.
Our SIP2SIM® service is available as an eSIM or a physical SIM card. eSIMs can be used in modern phones whilst physical SIMs can be used in an older phones.
The service uses 4G/5G VoLTE, but can normally fall back to older 2G services.
Once linked to an A&A number or your own SIP Server, the service can work just like a normal mobile phone with calls and texts:
Roaming throughout the EU, and US, is included (for up to 3 months in any year) at no extra cost. Other roaming is not planned, sorry.
We are offering a SIM with a high usage data package for £35.00 +VAT. The way this is sold to us is that it is unlimited but with a fair usage limit that we understand to be 100GB/month. When reached the service is throttled to a low speed, but one that should be sufficient for text based messaging apps to continue without problem.
The data package also allows limited hotspot functionality, 5GB/month, after which hotspot usage is throttled in the same way.
We may, in the future, be able to offer some lower fixed usage limited packages.
Note that data is always billed to end of current calendar month when adding data, and then in whole calendar months. i.e. removing data mid month does not remove data until start of next month - and then cannot be re-enabled until the month after (sorry, silly, I know, but that is the way it works).
Here is where you may find a use for SIP2SIM®
Don't want to put your personal number on your van?
Using the dual SIM feature in many phones you can add a second SIM, or more likely an eSIM, with a separate service and number.
Easy to have a work number on your phone, separate ring tone, recorded calls, set contacts to call/text from work number automatically (a feature on iPhones).
It does not even have to be an 07 mobile - why not have a proper local phone number to engender trust as a local tradesman?
Find out more about dual SIM working.
Some people spend as much time out on the road as in the office. By using a SIP2SIM®, your extension number can be set to ring both your desk phone and the mobile, making it easy for customers and colleagues to contact you.
As the SIM has the same feature set as any other SIP phone connected to the PBX, then features such as call recordings are also possible. Ideal for solicitors, those in the finance industry and others, whose regulatory requirements ensure they have a copy of their phone calls.
Adding an eSIM to a modern phone is quick and simple.
We can issue a number (landline or 07 mobile) and eSIM within minutes (paid with order).
We can do a service for as little as a month, or as long as you need. Even if you keep the number, you can simply disable the eSIM when not needed (still has month charges in that case).
Find out more about dual SIM working.
With the demise of old fashioned phone lines, why not move your existing landline number to your mobile phone.
Either as you main phone service, or an extra number on your phone using a second SIM or eSIM.
Our VoIP service allows porting in your old number, and our SIP2SIM® service allows for that to be used on your mobile phone.
Of course, we can also provide an old school phone for your home on the same number, or DECT cordless, working at the same time as your mobile. But these days so many people use just a mobile phone. This is perhaps ideal where mobile coverage is poor inside your home.
The mobile network behind SIP2SIM is officially supported on:
Unsupported phones may still work well but has just not been officially tested by the carrier. Smart watches are not supported.
SIP2SIM® is not a SIP app running on a smart phone over mobile data or WiFi! Having tried to make this work reliably, this was determined to be unpredictable at best, and completely useless at worst.
With this service your mobile phone is working as a mobile phone on the GSM mobile network using 4G/5G VoLTE; making and receiving proper mobile voice calls. GSM is a very mature technology, adept at handling changeovers between masts and packet loss, without breaking up.
And with most modern phones this can be a second line on the phone, ideal for home/work usage on one mobile phone. Find out more about dual SIM working.
The SIP2SIM® service makes your mobile work like a SIP device connected to a SIP phone system or VoIP provider of your choice. It can also be supplied pre-configured to an A&A VoIP number making your mobile work like a normal mobile phone but with a landline-style number.
The basic service allows you to specify, via our control pages, the server name, login and password for a SIP server. This could be your office phone system; an asterisk box, FireBrick or similar.. As long as it handles normal UDP SIP with G.711 A-law audio then the service will register to it as a phone and allow calls both ways.
This means your mobile handset becomes an office extension, like any other.
(Note, CLI shown on mobiles may be limited due to recent OFCOM rules)
Below is further information about the service:
Cost explanation
Changing data packages
When ordered, the SIM has no data allowance. You can change this at any time from the control pages, even right away. Your first month's data allowance and price for that allowance will be pro-rata to the end of the calendar month.
Calling emergency services
Calling 999 and 112 is possible.
Swapping between SIM and eSIM
It is not possible to convert a physical SIM to eSIM or an eSIM to a physical SIM. Instead, order a new SIM or eSIM and cease the old one.
Unsupported phones
SIP2SIM should work with most phones. However, there have been some cases where we have seen certain phones behave in a way that makes them unsupported. As of November 2024 we're aware of the Fairphone being incompatible due to the way it only holds a registration for an hour causing inbound calls to be intermittent.
Third party SIP services
The service involves entering SIP registration details in to our control pages. Where these are the details of your own SIP server such as an office phone system, you can make the decision as to whether or not you trust us with those SIP details in order to provide the SIP2SIM® service. We will, of course, use all reasonable skill and care to ensure the details remain confidential and are not disclosed.
We have, however, designed the service so that it can work with a wide variety of third party SIP services, not just in the UK but in various countries. There are a lot of unusual systems out there and we continue to work to ensure that such services operate with SIP2SIM®. However, using third party SIP details may well be in breach of your terms with the third party SIP provider as it means giving us your SIP details. It is up to you to check the terms and we would not suggest anyone breaks a contract they have. You may find that the provider is happy to trust us, especially if they do any other work with us, so it is worth asking. We are also happy to discuss contracts with other providers for the SIP2SIM® service and we may be able to provide them with branded SIMs to sell to their customers.
Unfortunately we cannot guarantee that the service will always work with all other providers, and whilst we aim to resolve any technical issues (with reference to the standards), if a provider simply will not deal with our service and blocks us there is little we can do.
Custom branding
Our voice and data SIM cards are ideal for a corporate network or for a wholesale customer to set up their own mobile service.
We can offer branding with professional quality SIM printing and pre-set settings.
We have a page with comprehensive list of technical details and restrictions and further articles in the knowledge base article which can be seen below.
