SIP Trunking for Business

Future-proof your business and start saving on calls

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The clock is ticking. In 2025 the UK’s ISDN network will be switched off and many legacy technologies such as telephone systems and fax machines will no longer work – is your business ready for the move?

Move away from legacy PSTN and ISDN services and opt for a cost-effective and straightforward alternative such as SIP Trunking. If you can still leverage services on your existing PBX, then SIP is the ideal solution.

2025 isn’t that far away, especially when considering such a pivotal change such as how your business communicates with your customers. Voice calls are not the only systems set to be affected by the move. Many businesses will use these analogue lines for other uses, including card machines, emergency alarms, door entry systems, lift lines, and remote monitoring systems, so you will have to consider these systems when planning your migration. Don’t put this off until it becomes a last-minute decision – future-proof your business today.



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Having provided landline services for more than 20 years, we know how to look after your network, which in turn means we also understand the challenges businesses face when transitioning to SIP.
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Benefits of Daisy SIP Trunking

Save money

IP connectivity costs less than ISDN. Free internal calls and lower line rental costs for multi-sites. Also, no expensive call-forwarding costs are required should you relocate or need to divert calls in the event of a disaster.

Business Continuity

If your office has to be temporarily relocated in an emergency, you can keep your business working – quickly and cost-effectively with SIP Trunk Call Manager.

Flexibility with phone numbers

Enables you to move offices while keeping the same geographic number without any ongoing call-forwarding costs.


Works seamlessly with each of the leading IP PBX brands in the UK market.


Business-grade resilience for your telephony during peak hours or in an emergency.

Line rationalisation

For businesses with multiple sites, SIP Trunking provides the opportunity for line rationalisation and reduces the number of PBXs you need to maintain – while retaining full control of the numbers associated with your business.

Microsoft TeamsCompatible with Microsoft Teams Direct Routing

Allows you to directly connect to the platform to make external calls.

Scale up and down

Ideal if you are moving and want to keep your existing numbers. Scale up lines during busy periods and back down again afterwards. You can split calls at any time. You are always in control.

Extend your reach with International SIP Trunks

UK businesses who are also operating overseas can make calls at a reduced rate, increase resilience and enable greater flexibility.

Our scale and expertise

With more than 20 years’ experience as a business communications provider, we understand the challenges businesses face when transitioning to SIP.

Act now to ensure your smooth transition away from ISDN

Your questions answered...

Download our guide to find out all the information you’ll need to navigate this landmark change in technology. (In a nutshell, it means you won’t be able to order new ISDN or PSTN services in the UK come 2023, and in 2025 Openreach will cease to provide dial tones or power to the lines which all equals: No. More. Calls.) We are working with Ofcom, communications providers, the Office of the Telecommunications Adjudicator (OTA), the Network Interoperability Consultative Committee (NICC) and trade bodies, to ensure where possible you experience a smooth migration.
If you use any of the following solutions, you need to start planning to include these in your migration: card machines, emergency alarms, lift-lines and help point systems, door entry systems, fax machines, remote monitoring equipment. Taking the time now to plan for the future and ensure voice and other phone dependent services are secure for the digital-first era will be vital to your business success.
Essentially, you need to start thinking of alternatives and changing the way your organisation communicates. There are options already available such as Voice over Internet Protocol (VoIP), which uses data networks to provide you with the same voice service but delivered in a slightly more modern way. It also means you can take advantage of more up to date collaboration tools.
Well, in the same way you probably wouldn’t rely on a car made over 30 years ago to get you to and from work every day, that’s pretty much what your voice traffic has been doing. Everything else has moved on – and now it is time for telecoms to catch up.
Not in the slightest. Daisy has been deploying VoIP services for more than 10 years now (we said it is time for telecoms to catch up). So trust us when we say that the sooner you start considering your options, the easier the transition will be for your business to start taking advantage of the opportunities that solutions such as VoIP can bring.

We know every organisation is different, that’s why we’ll ensure you get the support you and your business need to make an informed decision about your future – be that with an on-premise communications platform, deploying Session Initiated Protocol (SIP) connectivity or going the whole hog and moving to a fully-hosted cloud infrastructure.

Daisy offers an entire range of business-grade broadband and fibre options, alongside dedicated connectivity using Ethernet technology. We will work with you to provide the best option based on your business requirements. Take a look here.

Stop-sell applies at a premises level where that premise has access to an available FTTP product. Where a premise has access to FTTP there will be no new supply of other products, CP transfers, working line takeovers, addition of broadband to voice lines, or bandwidth modifications.

  • If a premise has GEA-FTTP available to order, then only GEA-FTTP is available to that premise and instantly become within the scope of stop-sell.
  • If a premise does not have GEA-FTTP available, SOGFAST, SOGEA, GEA-FTTC, SOTAP (where no fibre is available), MPF and WLR (only until September 2023) will be available.

The same stop-sell principles will apply for the fibre exchanges in Salisbury and Mildenhall. Openreach plans to modernise its network to support the delivery of telephone services using Internet protocol (IP) technology, and to upgrade its copper lines
to fibre. As part of this, it will undertake two trials:

The Salisbury trial (Dec 2020) will test the processes for migrating customers to fibre services and, ultimately, withdrawing legacy copper services.

The Mildenhall trial (May 2021) will test the processes for withdrawing Wholesale Line Rental (WLR), and migrating customers from legacy copper services to fibre – which will support the delivery of telephone services over broadband connections. MPF and SOTAP will be available in a fibre area if there is no spare fibre capacity.

Order journeys
• Existing product at a
• New premise
If the premise
If the premise is
for FTTP
Provision including new supply,
transfers and working line take
over etc.
Restricted No change –
this will follow
Stop Sell in

If the premise
has availability
for Single Order
products such
This should be
chosen over

Modify that increase the asset
base (including increase and
decrease of channels)
FTTC Provision and Modify
SOTAP and MPF Provision,
Speed Upgrade and Modify
Non Standard Lines (non-served
premises, short duration lines
and hot sites)
No change until
available on FTTP
As part of the FTTP exchange upgrade programme, any premises enabled for FTTP should have migrated to an FTTP solution, this also includes any premises connected to SOGEA.
Yes. Openreach has confirmed that this will most likely become a continual advancement as more and more FTTP is rolled out and are expected to release these details on a quarterly basis.
The PSTN supports a number of Openreach products: WLR3 analogue, ISDN2, ISDN30, LLU SMPF, SLU SMPF, Narrowband Line Share and Classic products. These products are generically referred to, as part of the industry programme, as WLR products. When the analogue network closes in 2025 these products will no longer be available.
In some circumstances where the customer is not in an exchange area that is impacted by the FTTP Exchange Upgrade stop-sell, they can migrate to LLU MPF (only where there is no FTTP availability).

You can migrate over to a Single Order broadband product. The voice service will stop working and effectively becomes redundant in this instance. Voice service will become an optional add-on to your broadband service. Download our quick-read, all-you-need-to-know guide about SOGEA >>

You can keep your current phone number if you inform your service provider at point of sale or when the migration order is placed, but you will need to take out an OTT IP Voice service (to run parallel with your Single Order Broadband product) and indicate that you wish to port the number onto the new IP Voice service otherwise you will lose the number once the service migrates away from the existing WLR or MPF service.
The 2025 WLR withdrawal date is not something that can be pushed back, this was defined as a necessity due to the BT Group PSTN network infrastructure reaching its end of life. This also means it is crucial that the other key dates leading up to the 2025 withdrawal date also do not get pushed back. This will of course be continued to be monitored as per updates directly from Openreach and Ofcom.
Daisy Corporate Services will work alongside you to ensure all of your services migrate/are upgraded to the new solution. At present there is no bulk order option in place, but all orders can be placed.
ATA stands for Analogue Telephone Adaptor. They are used to allow end users (EUs) to utilise their old hardware equipment. New Technicolor broadband routers and all models will include an ATA port later in 2020.
Yes, your ATA will convert your analogue signals to digital IP Voice but, in order to use this, you must have an IP Voice product over the top of your new Single Order broadband to transmit the calls.
Yes, if you are already on an FTTC enabled router then it will be compatible as SOGEA is built upon the same foundations. We are also awaiting updates from Openreach, Ofcom and market leaders in router technological specifications to confirm what will still be compatible and what hardware will become redundant.
SOGEA and FTTP orders will need to have a voice order placed alongside the migration order. These do not work like the current SIM2 orders so an OTT (over the top) voice order will need to be raised to run parallel with a significant amount of notice, in order for the number to port over to the IP Voice service.
It is imperative that you contact the vendor of these devices to confirm whether they are IP-compatible or not. If they are not, you will need to source new devices which are IP-compatible, to allow you to continue operating as a business. Otherwise, these devices will cease to work when moving to a Single Order product. If you need advice, get in touch and we can discuss your business requirements on 0344 863 3000.
Migrations between communications providers (CP) will still be available but the destination product they are migrating to will need to align with the stop-sell rules. Meaning that if the end-user (EU) is in the FTTP footprint, then they can only migrate over to FTTP.
Yes these features will be available until the stop-sell dates however, we would encourage that you arrange to migrate over to FTTP solutions with an OTT voice solution so that you are prepared and ready for when the PSTN is switched off.

Alternative copper and fibre products

Fibre to the Premises (FTTP) is the fastest and most resilient all-fibre product with broadband speeds of up to 1Gbps download and 220Mbps upload and can be purchased on its own.

Fibre to the Cabinet (FTTC) is a form of fibre optic communication delivery in which the optical fibre runs all the way from the exchange to the street cabinet and uses the existing copper network to reach the home or office. The remaining part of the access network from the cabinet to the customer is usually copper wire but could use other technologies such as wireless.

Single Order G.Fast (SOGFast) is a cutting-edge technology that delivers ultrafast speeds over existing copper lines of up to 330Mbps through a single order variant which forms part of the Openreach developing product portfolio.

Single Order GEA (SOGEA) Delivering superfast in a single order, speeds of up to 80Mbps will offer similar connectivity to FTTC without the need for an underlying Voice Access product. Download our SOGEA guide >>

Single Order Transitional Access Product (SOTAP) Supporting non-fibre areas with speeds of up to 17Mbps. This is a new product that will deliver a copper path between your premises and the SOTAP communication provider’s (CP) exchange infrastructure, over which the SOTAP CP can provide broadband and IP Voice services. This is different from a Metallic Path Facility (MPF) because it facilitates the use of existing exchange infrastructure which currently supports LLU SMPF and therefore provides a better experience when migrating away from WLR products (with or without SMPF).

Ethernet offers a wide choice of high bandwidth, permanentlyconnected point-to-point services designed to help CPs extend their own networks and deliver a range of high-quality services to their customers. The Ethernet fibre network that underpins them offers unrivalled geographic coverage of the UK, embracing many out-of-town locations where manufacturing takes place and where many data centres of the future will be located.

There are a number of options, including utilising the new Single Order Transitional Access Product (SOTAP) which uses broadband rather than voice as the primary service, as well as mobile and Ethernet services.
There is no option to opt out of the FTTP trail exchanges. If you have a working WLR or MPF asset in one of the exchanges you will be impacted by the stop-sell principles and rules with the expectation that the existing bases will be migrated onto an all IP solution/alternative product by the end of the trials in December 2022.
The withdrawal of PSTN copper services has a deadline of Dec 2025. The change is happening, and you do not want to be left behind. Both hosted voice and SIP are easily scalable for any growth aspirations – Daisy Corporate Services can help you migrate your services with minimum disruption to your business. For all your voice and data solutions we can get you connected.


Are You Switched On To The PSTN Switch-off?

Click here to download the step-by-step planning tool guide >