Reliable business telephone systems sit at the heart of every successful business. We have many years experience in delivering traditional PSTN telephone services that are reliable, improve efficiency and reduce costs for UK businesses.

Being a Tier 1 voice carrier, allows us to supply a range of telephony services – connecting offices, home and remote workers.

Our PSTN offering covers a variety of solutions for connectivity allowing businesses to take advantage of competitive call tariffs for national, international, non-geographic and mobile calls.

Direct Service

We provide a high quality, resilient and dependable phone service for businesses that are directly connected to the network. By taking ownership of all inbound and outbound calls, we are able to deliver customers a superior service.

Indirect Service

When the investment in a direct voice connection cannot be justified, i.e. for remote offices and home workers, we can provide indirect access, using different access technologies and circuit speeds. This connection method uses the BT network to pass calls to our network prior to the onward call delivery. This service is seamless to users and is a tried and tested approach to consolidating supply and billing.

  • Lower total cost of ownership through competitive minute rates and the completion of a thorough assessment of incumbent services
  • Network monitoring and alert service, monitoring customer's preferred Key Performance Indicators such as out-of-hours calls or weekly voice spend
  • Proactive support monitoring through CORETX’s highly trained support engineers, monitoring customer networks 24/7
  • Improved management and information statistics using CallWatch Interactive – real time call monitoring and call reports

Our unique combination of expertise, technology and broad range of voice and data services provide compelling reasons to implement our voice solution.

Lower Cost Line Rental

As part of our complete business phone system, we can supply your BT analogue, ISDN2 and ISDN30 lines. This not only means the convenience of a single bill covering line rentals and calls, but also a single supplier relationship for all voice services that reduces strain on customer resources.


We are able to novate existing BT circuits once the initial line rental contract expires. The process is straightforward and completely seamless, with no disruption to service. In addition, it can be carried out without changing existing telephone numbers.

Number Porting

Cherished and known local numbers can be retained and enhanced to remove the geographical boundaries typically associated with the BT local exchange. This removes any forwarding costs that would have been incurred for any organisation looking to retain existing numbers when moving 'out of area'.

We are able to supply DDI ranges from a supply of both geographical and non-geographical number ranges managed by us.

0300 are ideal for non-profit organisations and many business services, as they are geographically independent enabling both local and national organisations to present a common number, regardless of location. 0300 numbers are non revenue sharing and provide callers with rate certainty as the billing is treated the same as a regional geographic number.

  • Direct, resilient voice circuits bypassing the PSTN
  • Indirect access via Least Cost Routing (LCR) or Carrier Pre Select (CPS)
  • Line rental of ISDN and analogue lines
  • Transfer of ISDN and analogue lines from existing supplier to us

Reliable business telephone systems sit at the heart of every successful business and with PSTN solutions from CORETX you can lower the total cost of ownership. Competitive minute rates and the completion of a thorough assessment of incumbent services, ISDN channel usage and voice spend, eliminating unnecessary costs deliver a more cost effective solution.

Proactive support monitoring from our highly trained support engineers, monitors your networks 24/7/365 to identify and resolve any potential issues and raise alerts on out-of-hours calls or high weekly voice spend.

Improved management and information statistics are delivered using our call monitoring tool, CallWatch Interactive, which is accessible on line and enables you to view real time call monitoring, tailor call reports, and identify potential cost savings and trends across sites.