Microsoft Teams Phone System Direct Routing lets UK businesses connect their existing phone lines or SIP trunks directly to Teams. This transforms Teams into a full cloud PBX, combining chat, video, and PSTN calling in a single platform. Unlike Microsoft’s Calling Plans, Direct Routing gives businesses full control, letting you keep your telecom provider, retain existing numbers, and even run hybrid PBX setups during migration.
With the UK PSTN switch-off scheduled for 2025, Direct Routing provides a reliable, cost-efficient, and scalable telephony solution suitable for businesses of all sizes. Explore how your business can make the switch today.
What Is Microsoft Teams Direct Routing?
Think of Teams Direct Routing as a bridge between Microsoft Teams and the Public Switched Telephone Network (PSTN). A certified Session Border Controller (SBC) ensures that calls flow smoothly and securely, handling both inbound and outbound calls.
It’s basically taking your current phone system, plugging it into Teams, and instantly making it smarter, more flexible, and scalable.
Retain geographic (01/02) and non-geographic (03/08) numbers
Use your current telecom provider
Enable cloud benefits anywhere access, GDPR compliance, and Teams integration
Avoid buying expensive Microsoft phone bundles you might never use
How Microsoft Teams Direct Routing Works in UK
Here’s a simple breakdown for UK businesses:
- SIP Trunk Connection: Your SIP trunk connects to a certified SBC (cloud, software, or hardware).
- Secure Call Routing: The SBC routes inbound and outbound PSTN calls into Teams.
- Teams Client Access: Staff make and receive calls via Teams on desktop, mobile, or certified handsets.
- Scalable Deployment: Works for single-site offices or multi-location enterprises.
This setup reduces reliance on legacy PBX hardware while letting you migrate gradually, avoiding downtime and business disruption.
Why UK Businesses Are Switching to Teams Direct Routing
1. Cost Savings with SIP Trunks & BYOC
- Bring Your Own Carrier (BYOC) with providers like BT, Gamma, Virgin, or Colt.
- Avoid Microsoft Calling Plan fees (£12+/user/month), paying usage-based SIP rates (£5–15/user + calls).
- Many SMBs cut telephony costs by 30–50%.
2. Hybrid & Remote Work Ready
- Run legacy PBX alongside Teams during migration.
- Full number porting ensures continuity.
- Global calling from any device, ideal for hybrid teams.
3. Unified Communications in One Platform
- PSTN calls, chat, video, and file sharing all GDPR-compliant.
- Centralised management via Teams Admin Center; no extra hardware needed.
4. Future-Proof for PSTN Switch-Off
- Certified SBCs ensure compliance with the 2025 UK PSTN switch-off.
- Supports emergency calling, redundancy, and reliable VoIP connectivity.
Need a hassle free Direct Routing Set Up
Key Considerations Before Deploying Teams Direct Routing
Before starting, keep these points in mind:
1. SBC Selection
The right Session Border Controller affects call quality, security, and ongoing maintenance. Certified options include Ribbon, AudioCodes, and Oracle.
2. Carrier Quality
Your SIP provider determines call reliability. BYOC is flexible, but selecting a low-quality carrier can cause jitter or latency.
3. Number Porting
Porting geographic and non-geographic numbers usually takes 5–10 working days. Proper scheduling avoids downtime.
4. Voice Routing Policies
Dial plans, voice routes, and emergency call rules must be configured correctly for compliance and smooth operation.
5. Network Readiness
Ensure bandwidth, QoS, and firewall rules can support real-time voice traffic. Most call quality issues come from local network misconfigurations, not Teams or SIP trunks.
How to Set Up Teams Direct Routing in the UK Step-by-Step:
1. Prepare Your SBC
Connect SIP trunk, configure routing rules, test codecs, and validate UK number formats.
2. Register SBC in Teams
3. Port or Assign Numbers
Supports geographic, non-geographic, and toll-free lines.
Porting usually takes 5–10 working days
4. Configure Voice Routing Policies
Create voice routes and dial plans via Admin Center or PowerShell.
Assign routing policies to users.
5. Test Before Rollout
Check caller ID, PSTN stability, call queues, and auto-attendants.
Start with a small pilot (5–10 users), then scale gradually.
Teams Direct Routing vs Teams Calling Plan (UK Comparison)
Feature | Teams Calling Plan | Teams Direct Routing |
Carrier Choice | Microsoft only | BYOC (BT, Gamma, Colt…) |
Number Porting | Limited | Retain all UK numbers |
Cost | Fixed monthly fees | Usage-based, often cheaper |
PSTN Connectivity | Microsoft PSTN | SIP trunks, PBX, hybrid |
Hybrid Support | No | Yes |
Best For | Micro teams | SMBs & enterprises |
Direct Routing is the clear winner for long-term flexibility and carrier control.
FAQs: Microsoft Teams Phone System Direct Routing (UK)
Can I keep my existing UK phone numbers?
Yes. Microsoft Teams Direct Routing lets you retain geographic (01/02), non geographic (03/08), and premium numbers. Porting ensures calls continue without disruption, maintaining continuity for clients and partners.
How much does SIP trunking cost?
Costs typically range from £5–15 per user per month, plus call charges. This is generally cheaper than Microsoft Calling Plans and allows flexibility—pay for what your business actually uses.
Is Direct Routing suitable for small businesses?
Absolutely. Direct Routing scales from just a few users to large enterprises. Small UK businesses benefit from cloud PBX features, mobile calling, and reduced hardware investment.
Which SBCs support Teams Direct Routing?
Certified SBCs include Ribbon, AudioCodes, Oracle, and Ferrari Electronic. Many UK businesses opt for cloud-hosted SBCs to simplify setup, maintenance, and scalability.
How long does deployment take?
Deployment usually takes 1–3 weeks depending on setup complexity. Porting numbers, configuring SBCs, and testing call flows may extend timelines for larger or multi-site organisations.
Ready to Upgrade? Free UK Consultation
Modernise your telephony, streamline communications, and cut costs with Microsoft Teams Phone System Direct Routing.
Our UK experts handle:
- SBC deployment
- SIP trunk integration
- Number porting
- Routing policie.
- Testing and optimisation
- Ongoing monitoring and support
Whether you’re moving from BT ISDN, a legacy PBX, or another cloud system, we ensure a smooth, secure transition.
Transform your business communications With Direct Routing
