Case Study: 3CX VoIP Rollout for a 5-Site UK Windows & Doors Manufacturer

CASE STUDY · 3CX VOIP DEPLOYMENT

Replacing ISDN with cloud-based 3CX across five UK sites and 150+ staff.

A family-run UK windows and doors manufacturer moved off legacy ISDN ahead of the switch-off, unifying mobile, deskphone, headset and video conferencing on a single cloud platform. Their senior team now runs multi-location video conferences as standard.

Sector: Manufacturing (windows & doors) · Sites: 5 UK locations · Staff: 150+ · Year: 2022

Certified 3CX Partner · Microsoft Teams Phone · UKAS ISO/IEC 27001:2022 · RIPE NCC Member

Reviewed by Jez Walton, Managing Director, System Force IT · Published 2026-05-18

UKAS ISO/IEC 27001:2022 Certified · Microsoft Solutions Partner · Certified 3CX Partner · RIPE NCC Member

The client

A family-run UK manufacturer of windows and doors, founded in the mid-1980s, supplying the commercial and trade market. The business operates from five UK sites with more than 150 staff. System Force IT has supported the business for over a decade, originally through server hosting services, then expanding across all telecommunications and IT including laptops, conferencing equipment, broadband, wireless and email security.

The issue

The business was approaching the end of its contract for its existing ISDN phone system, against the backdrop of the UK PSTN and ISDN switch-off. They needed a new phone platform that could:

  • Unify communications across five sites and 150+ staff.
  • Support mixed working patterns: office, warehouse, home and mobile workers.
  • Reduce per-call costs and remove the per-extension hardware tax of ISDN systems.
  • Stand up reliable video conferencing for a senior management team operating across multiple sites.
  • Scale with the business without further capital outlay.

ISDN had become a tax on growth. Every new extension meant more hardware. Cloud removed the tax.

The solution

Following a working demonstration at System Force IT’s Gloucester offices, the recommendation was a cloud-hosted 3CX VoIP deployment, with the business taking an annual licence model that allowed extensions to be added on demand.

Technical detail

  • Platform: 3CX VoIP, cloud-hosted, integrated with the existing IT estate.
  • Endpoints: mixed estate of desk handsets, headsets with laptops, and softphones; the 3CX app deployed to every staff mobile and laptop.
  • Inter-site dialling: VoIP-to-VoIP calls between sites and home workers are free of per-minute cost.
  • Video conferencing: built-in 3CX video used routinely by senior management. A recent example saw the chairman conferenced into a meeting with 12 staff dialled in from six different locations.
  • Licensing: annual licence with unlimited extensions, removing the per-extension hardware-card costs of the previous platform.
  • Continuity: when COVID-19 hit, the same digital platform let receptionists answer the main line from home with laptops and headsets without service interruption.

Outcome

Communications unified

Warehouse to boardroom, all on one platform: deskphone, mobile, laptop or headset.

Productivity uplift

Internal relations and productivity reported as materially improved; quicker, easier contact between sites.

Lower travel, lower emissions

Multi-site senior meetings now run by video rather than by car; meaningful environmental and time saving.

Resilient through COVID

Receptionists answered the main line from home; no main-number outage during lockdowns.

Scalable cost model

Annual licence with unlimited extensions removed the per-extension hardware tax that ISDN imposed.

Support response when it mattered

Including a documented 3am support call resolved on first contact.

Client feedback

“3CX has completely revolutionised our communications, making it easier to speak to those we contact regularly, and opening up new lines of communication with staff that we may not have had before. I would say it has undoubtedly improved internal relations and productivity, as people from the warehouse to the boardroom can now communicate quickly and easily via the 3CX app on their mobile, desk phone or laptop.”

“The video conferencing system has been extremely useful to us, particularly to our senior management team. It is a far better use of everyone’s time to meet in this way and, of course, better for the environment, not having staff driving hundreds of miles to attend a single meeting.”

“As with any new system, there can be teething problems. When I called their support line at 3am one morning, they were there, immediately, helping us to resolve the problem. After so many years, we trust the System Force team implicitly.”

– IT Manager, UK windows and doors manufacturer (5 sites, 150+ staff)

Planning your own PSTN-to-VoIP migration?

The UK PSTN and ISDN switch-off completes in January 2027. We are a Certified 3CX Partner, run our own UK data centres and have migrated multi-site businesses off legacy systems for years. Tell us where you are today and we’ll come back with a like-for-like cost comparison and a migration plan.

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Related: Business Telephone Systems · Business VoIP Worcester · Business VoIP Gloucester · PSTN Switch-Off January 2027 · Managed IT Services.