Phone Line Options for Shops and Shopping Centres

For your phone system to be effective and reliable, you need to consider what type of phone line will be the best fit for your retail business to get the calls to and from your phone system.

A phone line needs to give your retail unit:

Flexibility with your phone numbers– High voice quality – Business Continuity– Capacity to grow, easily


There are two main options for phone lines:

  • ISDN Phone Lines are a traditional type of phone line which uses physical lines to transmit voice calls. You won’t be able to purchase any additional lines past 2023. This technology is being switched off between April and December 2025.
  • SIP Phone Lines uses virtual lines to transmit a phone call. You can quickly add/remove lines, have a high voice quality and lower call costs. It is a far more flexible phone line solution than ISDN.

Should you choose a SIP Line; you may want to explore a phone line management solution which increases your control over your phone numbers and how calls come into your business. We recommend SIP Trunk Call Manager or Inbound Phone Line Management

There isn’t one size, fits all, so please do get in touch to discuss your requirements!

ISDN Phone Lines

ISDN (Integrated Service Digital Network) has traditionally, been considered the main solution for businesses when it comes to their phone line.

It is a set of digital communication standards for the transmission of voice and data. It consists of physical copper and fibre optic lines connected via telephone exchanges across the world.

ISDN Switch Off

ISDN Phone lines are slowly being phased out; from September 2023, BT will withdraw the ability to purchase additional ISDN phone lines. Between April and December 2025, there will be a forced migration period before they switch them off.

The key thing is not to panic as you do have until September 2023 to purchase any additional lines, so as long as you purchase any phone lines you may need then you are fine for another few years.

Regardless of when you choose to make a change, it is still a good idea to think about your options are and plan it in, now. The good news is that if you do that now, it is a planned expenditure and not a surprise.

SIP Trunks

SIP and SIP trunks is an on-premise or hosted solution for a telephone system that will use virtual phone lines rather than physical wires.

Session Initiation Protocol (SIP) is the set of rules that allows you to initiate and terminate a communication session, whether it’s a voice call between 2 people or multiple calls between a whole team, using an IP address.

SIP trunking (also commonly referred to as a SIP Phone Line) connects your site directly into the network (the ITSP), via an IP connection which will carry out and terminate your inbound and outbound voice calls across your PBX.

SIP Trunking is fast becoming the best alternative to ISDN as it is cheaper on a per line basis, it offers flexibility and control over your phone numbers and quick to deploy.

Our service can support connections ranging from two channels for a small PBX-equipped business to an unlimited number of channels for large businesses or retail businesses that have contact centres.

Benefits of SIP and SIP Trunking

Any retail business with a PBX can switch to our SIP trunking service and immediately benefit from more flexible, less expensive and more resilient phone service. Here are our top five benefits for upgrading your phone system to SIP:

  • Save Money on call costs and line rental – IP connectivity costs less than ISDN so you’ll benefit from lower call costs; free internal calls between sites and free calls to UK local/national and mobiles. Typically, you are looking for saving of up to 50% on line rental and 25% or more on call costs.
  • Flexibility with phone numbers – SIP trunking enables you to reduce the number of PBX’s you need to maintain whilst maintaining your existing phone number(s) regardless if you move office.
  • Scalability – SIP Trunks are perfect if you are growing (or downsizing) and you want to retain your phone numbers. You are always in control because you can add lines, remove lines and split calls at any time.
  • High Quality – We can proactively monitor and manage the quality of service across the entire network. We are able to support both G.729 or G.711 codecs.
  • Business Continuity – Should your shop need to be relocated, SIP trunking allows you to take your phone lines with you quickly and cost-effectively.

SIP Trunk Call Manager

SIP Trunk Call Manager provides you with all the benefits of SIP Trunks together with feature-rich, centralised call control. This includes our market-leading call bundles and the only fraud management tool that financially indemnifies you against loss.

SIP Trunk Call Manager can benefit your shop or shopping centre if you need a solution offering powerful business continuity or the ability to fully manage your entire number estate directly via your SIP trunks.

Inbound Call Manager

Inbound gives you full control of your phone numbers and the calls that come into your retail business.
Inbound is great for simple call routing through to large-scale call centres.

You can route, monitor and manage your calls, easily, without being reliant on a network operator to make the necessary changes for you. You’ll be able to identify key metrics such as the volume of missed calls, waiting times etc so that you are able to pull reports that are relevant to you which means you’ll be able to create changes in your business to ensure all calls are managed by the right people, consistently, throughout quiet and busy periods.

You can make changes using a mobile app or via the online portal.

Benefits of Inbound

  • No set-up costs – Just a monthly fee to use the software.
  • Use with any number – You can use Inbound with any phone number, geographic (such as 01/02) and non-geographic (08/03) numbers.
  • Improve your Customer Service – Ensure your business answers every call by putting rules in place if your staff are busy. Additionally, you can record calls for training purposes (or for compliance.) You can even make and upload your own voice announcements to provide customers with routing options or advise them on opening hours or website address.
  • Build your own call plans – You can build and modify your call plans according to your business needs; this means you can dictate what happens to calls outside of business house as well as diverting options for busy periods.
  • Business Continuity – In the event of a disaster or an outage, you can redirect calls to another site. You can use Inbound with any number, from anywhere and with any device.
  • Free App / Online Portal – Make any changes, quickly using the online portal or the free app.
  • Advanced Call Reporting – You can use Inbound to report on how you are measuring against your KPI’s. For instance, you can look at productivity, call patterns, caller behaviour, waiting time and how long it takes to answer calls. You can set the reports and schedule them to be sent on a regular basis to up to three email addresses.

SIP Trunk Call Manager vs Inbound

SIP Trunk Call Manager is integrated directly with the SIP product whilst Inbound is a standalone product; they are both fairly similar although the pricing structure is different.

SIP Trunk Call Manager is an option that can be activated or deactivated; it’s not mandatory but the activation is done within the customer’s SIP Trunk Endpoint / account.

With Inbound, it is a smart diversion system but not limited to SIP trunks, it can be loaded to use on mobiles and other phone lines e.g., ISDN.

Learn more about how SIP can help your business

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