A telephone and VoIP installer designs, installs and configures voice communications systems for commercial, institutional and high-specification residential premises. With the BT Openreach PSTN and ISDN switch-off underway across the UK, businesses that still rely on traditional copper telephone lines or ISDN circuits need to migrate to Voice over Internet Protocol (VoIP) systems. VoIP installers assess existing infrastructure, design the replacement IP PBX or cloud-hosted telephone system, install handsets and headsets, configure call routing, and integrate with unified communications (UC) platforms such as Microsoft Teams and Cisco Webex.
What they do
- Design and install IP PBX telephone systems (on-premises and cloud)
- Migrate PSTN and ISDN lines to SIP trunks and VoIP services
- Configure VoIP handsets, softphones and headsets
- Deploy Microsoft Teams Rooms and Cisco Webex communications platforms
- Install structured cabling and PoE (Power over Ethernet) switching for VoIP
- Set up call centre infrastructure, auto-attendants and hunt groups
- Configure hotel and hospital internal communications systems
- Provide ongoing support, maintenance and user training
When you need one
A VoIP installer is needed when you are fitting out new commercial premises, migrating from legacy telephone systems, or upgrading to unified communications.
Typical costs (UK, 2025)
| Job type | Typical cost |
|---|---|
| Small office VoIP setup (cloud PBX, up to 10 users) | £500 - £2,000 |
| On-premises IP PBX (20-50 users) | £3,000 - £12,000 |
| ISDN migration (per line / DDI group) | £200 - £800 per group |
| Microsoft Teams Rooms (per room) | £2,000 - £8,000 |
| Call centre platform (per agent seat) | £500 - £2,000 per seat |
| Structured cabling for VoIP (per point) | £60 - £120 per point |
Cloud-hosted VoIP systems typically charge a monthly subscription per user (£5-£25/user/month) in addition to installation costs. On-premises IP PBX systems have higher upfront costs but lower ongoing fees.
Qualifications to look for
Cisco Certified Network Associate (CCNA) Collaboration or CCNP Collaboration confirms competence in Cisco-based VoIP and unified communications platforms. Cisco is one of the most widely deployed enterprise telephony systems globally.
Microsoft Certified: Teams Administrator Associate or Teams Rooms-specific certifications confirm competence in deploying and managing Microsoft Teams Rooms and Direct Routing for Teams Phone. Relevant for organisations using Microsoft 365.
How to find a reputable telephone and VoIP installer
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What is the PSTN switch-off and do I need to migrate to VoIP?
The Public Switched Telephone Network (PSTN) and ISDN services are being switched off across the UK as part of BT Openreach's modernisation programme. The switch-off is being phased by exchange area, with all legacy analogue and ISDN services expected to be replaced by digital (VoIP/SIP) services by late 2025. Any business or organisation still using PSTN telephone lines, ISDN2 or ISDN30 circuits will need to migrate to a VoIP-based solution. A specialist VoIP installer can assess your existing setup and design a migration path.
What is an IP PBX and how does it differ from a traditional phone system?
An IP PBX (IP Private Branch Exchange) is a telephone system that uses Internet Protocol (IP) networking to carry voice calls, rather than traditional copper telephone lines. Unlike a traditional analogue PBX, an IP PBX can route calls over the internet or a corporate network, integrate with computer software, enable mobile and remote working, and support video calling and instant messaging as part of a unified communications (UC) platform. IP PBX systems can be hosted on-premises, in the cloud, or as a hybrid.
What certifications should a VoIP installer have?
Look for vendor certifications from the telephony platforms they install - Cisco Certified Network Associate (CCNA) or Cisco Collaboration certifications for Cisco-based systems; Microsoft Teams Rooms certifications for Microsoft-based unified communications; and Avaya, Mitel or 3CX certifications for other common systems. For structured cabling supporting VoIP, look for Nexans, Belden or Leviton installation accreditation. There is no single UK regulatory body for VoIP installers, so vendor certification and documented experience are the key indicators of competence.