Direct Routing vs Operator Connect: Which One to Use

Short answer: Direct Routing vs Operator Connect is a control-versus-simplicity decision for Teams Phone PSTN. Direct Routing means you (or your integrator) run certified SBCs, SIP trunks, and voice routing. Operator Connect means a Microsoft-approved operator enables numbers and PSTN in the Teams admin center with far less SBC work for you. Calling Plans are Microsoft’s own PSTN minutes/numbers in supported countries — often the fastest path for small footprints, not a third “SBC mode.” Choose Direct Routing for complex/legacy/hybrid voice. Choose Operator Connect when a supported operator covers your countries and you want operator-managed connectivity. Choose Calling Plans when Microsoft’s markets and pricing fit and you do not need custom SBC control.

Direct Routing vs Operator Connect vs Calling Plans

	Direct Routing	Operator Connect	Calling Plans
Who brings PSTN	Your SIP trunk + SBC	Operator connected to Microsoft	Microsoft
SBC you manage	Yes (certified)	Usually no (operator side)	No
Voice routing policy / dial plan	You design deeply	Still needed for some scenarios; less trunk engineering	Mostly service dial plans; light routing
Legacy PBX / contact center trunks	Strong fit	Depends on operator offerings	Weak fit for complex hybrid
Multi-country patchwork	You stitch trunks	Operator coverage map matters	Only where Microsoft sells plans
Ops burden	Highest	Medium (operator + Teams admin)	Lowest

What Direct Routing is

Microsoft Teams Direct Routing connects Teams Phone to the PSTN through a certified Session Border Controller. Teams signals to your SBC; the SBC signals to your SIP trunk or legacy gear. You own certificates, TLS options, firewall rules, codecs, number inventories on the SBC, and dial plans plus voice routing policies.

Use Direct Routing when you need at least one of:

Existing SIP trunks or carrier contracts you will not replace
On-prem PBX, contact center, or analog/FXO leftovers that must stay
Advanced call flows, local breakout, or SBC features (transcoding, header manipulation, recording integration)
Countries or number types an Operator Connect operator does not cover for you
Media path control such as media bypass or Local Media Optimization designs

Cost is not only licenses. Budget SBC HA, monitoring, certificate lifecycle, and someone who can read a SIP trace. When it breaks, start with Direct Routing troubleshooting — Inactive gateways and SIP 403s are yours to solve.

What Operator Connect is

Operator Connect lets a participating telecom operator enable PSTN calling for your tenant through Microsoft’s Operator Connect ecosystem. In practice you pick an operator, they assign/port numbers, and Teams Phone users get PSTN without you building Direct Routing SBCs for that traffic.

Use Operator Connect when:

A supported operator covers the countries and number types you need
You want faster enablement and operator-managed voice infrastructure
You do not want to run SBCs, or you want to shrink the SBC estate to special cases only
Procurement prefers an operator Teams relationship over DIY SIP + SBC

You still administer Teams Phone users, emergency calling where applicable, and some policies. You give up low-level SIP control. If the operator has an outage or cannot offer a specialty trunk, you cannot “fix the SBC” — you open a ticket with them.

Where Calling Plans fit

Microsoft Calling Plans are Microsoft-provided PSTN numbers and minutes (or pay-as-you-go variants where offered). No SBC. No Operator Connect operator. Teams Phone + Calling Plan license + available inventory in that country.

Calling Plans fit when:

User counts and countries are in Microsoft’s Calling Plan markets
You want the shortest path to dial tone for knowledge workers
You do not need custom SIP integration or on-prem voice hairpins

Calling Plans struggle when you need complex hybrid voice, non-supported countries, or deep integration with existing PBX/contact center platforms. Many enterprises mix: Calling Plans or Operator Connect for simple sites, Direct Routing for contact centers and legacy.

Decision tree

Do you must keep SIP trunks, PBX, or contact-center SBCs under your control? → Direct Routing (possibly alongside another model for other users).
Else: is Microsoft Calling Plans available and enough for those users/countries? → Calling Plans.
Else: is there an Operator Connect operator that covers you commercially and technically? → Operator Connect.
Else: Direct Routing, or a multi-model tenant (very common).

Multi-model is allowed. Example: Operator Connect for offices in two countries, Direct Routing for a global contact center trunk, Calling Plans for a small pilot team in a Microsoft market. Keep voice routing policies clean so traffic does not accidentally match a catch-all Direct Routing pattern. Microsoft documents that Direct Routing patterns are evaluated in ways that can surprise you if Global routing contains .* — use custom policies and deliberate usage order.

Comparison details that matter in RFPs

Numbers and porting

Direct Routing: you port to your SIP carrier; Teams only needs the number assigned to the user/resource account and routing to your SBC. Operator Connect: porting and inventory follow the operator’s process. Calling Plans: Microsoft inventory and port-in rules.

Emergency calling

All three require a real emergency plan for each country. Direct Routing often means more dynamic emergency routing design on your SBCs. Operator Connect and Calling Plans shift more of the PSTN emergency path to the provider, but location (LIS / trusted IP / dynamic location) is still your Teams problem.

Survivability and branch

Direct Routing can pair with local SBCs and branch survivability patterns. Operator Connect and Calling Plans are cloud PSTN — treat WAN failure as “no PSTN” unless you add a separate local solution.

Compliance and recording

If you require specific SBC-level recording or SIPREC integrations, Direct Routing usually wins. Confirm Operator Connect operator capabilities before you assume feature parity.

Migration patterns that work

PBX to Teams with existing SIP trunks: Direct Routing first; later evaluate Operator Connect if you want to retire SBCs.
Greenfield Microsoft 365 shop in one Calling Plan country: Calling Plans; revisit if you expand to unsupported regions.
Global enterprise standardization: often Operator Connect where available + Direct Routing for exceptions, not a single slogan for every site.
Pilot: prove dial plan, emergency, and user experience on one model before you dual-run three.

Common mistakes

Buying Direct Routing SBCs “because enterprise” when Operator Connect already meets the countries and you have no legacy trunks.
Choosing Operator Connect without checking number types (toll-free, shared cost, national) and contact-center needs.
Assuming Calling Plans cover every subsidiary country.
Leaving a Global voice routing policy with broad Direct Routing patterns that steal calls from Calling Plan users.
Skipping dial-plan design — users still dial local habits; normalization is not optional. See dial plan vs voice routing policy.

Practical recommendation

Write the decision as constraints, not preference:

List countries, number types, legacy systems, and contact-center trunks.
Mark each row: Calling Plans / Operator Connect / Direct Routing / mix.
Only then pick SBC vendors or operators.

Direct Routing vs Operator Connect is settled when you know who must own the SIP edge. Calling Plans enter when Microsoft’s PSTN is enough and you want minimum voice infrastructure.