Replacing PBX with Microsoft Teams Phone: Migration Guide for UAE Businesses

Teams Phone is the phone system inside Teams: calling, voicemail, auto attendants, call queues and transfers. But the phone system on its own does not connect to the public telephone network (PSTN). That connection, which lets you dial a mobile or receive a call on your office number, comes from somewhere else. There are three ways to provide it:

Why? Voice services in the UAE are regulated. The Telecommunications and Digital Government Regulatory Authority (TDRA) requires PSTN voice and SIP trunking to be provided by licensed carriers, which means e& (Etisalat) and du. A foreign cloud provider cannot simply supply UAE numbers and minutes. So in practice, Teams Phone in the UAE means Direct Routing to a licensed UAE carrier.

Two practical consequences:

• Do not buy a Microsoft Calling Plan for UAE users. It will not work for UAE numbers, and the plan will not help you.

• Do not route calls through unlicensed third-party VoIP providers to save money. It creates regulatory risk and is not worth it for a business phone line.

Internal Teams-to-Teams calls and meetings are separate from the PSTN and work as normal. The regulated piece is connecting to the public phone network. If your policy depends on exactly what is allowed, confirm it with your carrier.

Direct Routing links three pieces:

• Teams Phone (the user licence and the Teams side).

• A Session Border Controller (SBC), a certified device or service that sits between Teams and your carrier, translating and securing the calls.

• A SIP trunk from e& or du, carrying your UAE numbers and call minutes.

The SBC can be:

For most companies moving off an ageing PBX, a managed SBC is the simplest way. It removes the hardware and certificate management, while giving you the same routing capability. Keep an on-premises SBC where you must integrate lifts, door entry, fax or a PBX you plan to retire gradually.

Most delays come from surprises discovered late. Before you design anything, gather:

Contracts

• PBX maintenance and support contract: term, renewal date, notice period and termination charges.

• Hardware lease or ownership.

• Carrier contract: lines or channels, numbers, term, price and any early-exit fees.

• Any call-recording or call-centre contracts.

Telephony inventory

• Every direct number (DID), main number, fax number and special number.

• Users, extensions and who actually uses a phone.

• Call flows: reception greeting, hunt groups, queues, IVR menus, after-hours routing, voicemail and call recording.

• Peak concurrent calls (from carrier or PBX reports). This sizes your trunk channels.

• International calling patterns.

Special devices

• Analogue phones, fax machines, door intercoms, lift emergency phones, paging systems and alarm dialers.

• Integrations: CRM, hotel property management systems, contact centre software, building management.

• Our guidance on VoIP in hospitality IT support covers property-management integration, which is the most common complication in hotels.

Network and sites

• Bandwidth, Wi-Fi quality, switches with power over Ethernet and internet resilience at each site.

Every user making or receiving PSTN calls needs a Teams Phone licence. It is included in Microsoft 365 E5 and available as an add-on for other plans, so check what you hold today. If you are already deploying E5, the licence cost is largely absorbed. Our Microsoft 365 setup guide covers licensing, and our comparison of Microsoft 365 and Google Workspace may help if you are still choosing a platform.

Plan this with your carrier early, because it is often the slowest part.

• Numbers are issued by the licensed carriers. The usual approach is to keep your existing numbers with your current carrier and deliver them to Teams through the SIP trunk and SBC, rather than moving them to a new provider.

• Do not assume porting between carriers. Moving a number from one UAE operator to another may be limited, slow, or not permitted for some number types. Ask both carriers in writing before you plan a change of provider.

• Keep your main number safe. It is the one that customers know. Test it before cutover and have a rollback plan.

Rebuild reception, auto attendants and call queues in Teams. Record greetings in Arabic and English where your callers expect it. Decide who handles after-hours calls, public holidays and Eid closures.

Confirm how calls to UAE emergency numbers will be handled from Teams users, including those on laptops and mobiles, and how location information will be provided. Test it with your carrier before go-live. Do not assume Microsoft's emergency-calling features behave in the UAE as they do elsewhere.

If you record calls, you must handle consent and storage properly. Recording and retaining voice data engages data protection and privacy obligations, including the PDPL. See our overview of UAE cyber and data laws, and check recording rules for your sector.

Not everyone needs a desk phone.

Buy Teams-certified devices only, and test a sample before ordering in bulk.

Voice is sensitive to network quality. Plan for roughly 100 kbps per call as a budgeting figure, quality-of-service marking on the LAN, good Wi-Fi coverage, and internet resilience. Dual internet lines from different carriers are worth the cost if telephony depends on them. Add an SBC high-availability design if calls are business-critical, and make sure the SBC and network equipment sit on UPS power.

The question finance asks is "will this cost less?" The honest answer is: not always on the phone line items alone. The saving usually comes from avoiding PBX refresh costs, consolidating tools and removing separate maintenance contracts.

Take an 80-user company with 20 desk phones. The figures below are assumptions for illustration only. Use your own quotes.

Reading the example:

• The result is close to break-even once the PBX refresh is included. If the PBX needs no refresh, keeping it can be cheaper on paper.

• If you already hold Microsoft 365 E5, the licence line falls to roughly zero and Teams comes out about AED 86,000 cheaper over three years in this example.

• The case gets stronger with more remote staff, multiple sites, or when you can retire other tools such as a separate softphone and conferencing platform.

The strongest reasons to move are often operational: calls follow people to laptop, mobile and desk; one admin portal; simpler changes; and one less ageing system to keep alive. Weigh those against the migration effort.

Avoid a single weekend "big bang" for the whole company.

Run the PBX and Teams in parallel until you are confident. Many companies use SBC routing to send some numbers to Teams and others to the legacy PBX while migration is in progress. Schedule cutovers outside peak periods and keep staff on hand for the first business day.

• Reception first. The receptionist is the heaviest phone user and the most visible. Train and equip them properly, and agree call-handling procedures.

• Show the benefits. Calls on the laptop and mobile, voicemail in email and transfers with a click.

• Short guides and drop-in sessions in English and Arabic.

• Headset policy. Good headsets make a bigger difference to experience than any other purchase.

• Clear support route for the first weeks.

• UAE experience: has the partner delivered Direct Routing with e& or du before, and can they name a reference?

• Carrier relationships: who holds the trunk contract, and who is responsible when the carrier fails?

• SBC design: redundancy, certificates, monitoring, and who supports it out of hours.

• Number and routing plan: a written plan, including your main number and rollback.

• Emergency calling: a tested process.

• SLA: response and resolution times for voice faults, which are more urgent than most IT tickets.

• Call quality monitoring and reporting.

• Exit terms: you should be able to take your configuration and numbers with you.

• Security: SBC hardening and toll-fraud protection, since PBX and SBC fraud is a real risk.

• Planning for Calling Plans and discovering at the last minute they are unavailable.

• Underestimating number logistics. Carrier lead times and requirements can set your timeline.

• Forgetting analogue devices, lifts, door entry and fax.

• Ignoring network quality, then blaming Teams for choppy calls.

• No rollback plan for the main number.

• Skipping toll-fraud protection on the SBC and carrier trunk.

• Cancelling the PBX contract too early, leaving no fallback.

• Treating telephony as an afterthought in a wider office IT setup project, when reception depends on it every day.

Americana helps UAE organisations plan and deliver PBX-to-Teams migrations: contract and inventory review, Direct Routing and SBC design with e& or du, number planning, handset and headset selection, network readiness, pilot, phased cutover and user training. We will also tell you plainly if keeping your PBX for another year is the cheaper choice. Book a telephony migration assessment and we will map your current system, your options and a realistic cost.

1. What does Teams Phone need beyond a Microsoft Teams licence?

A deployment needs the appropriate phone-system licensing, a supported connection to the public telephone network and a design covering numbers, call flows, devices and support.

2. What is Direct Routing?

Direct Routing connects Teams Phone to a telephony provider through a supported Session Border Controller. Carrier arrangements and service availability must be confirmed for the deployment.

3. What should be checked before replacing a PBX?

Inventory contracts, numbers, call flows, analogue devices, emergency calling, recording requirements, handsets, network quality and rollback dependencies.

4. How can a business reduce telephony cutover risk?

Pilot first, test call flows and quality, coordinate number changes with the carrier, migrate in phases and keep a documented rollback option.