UnlimCall × Microsoft Teams

Plug UnlimCall in as the PSTN trunk behind Teams Phone via Direct Routing. Same Teams client your team already uses — real local numbers in 33 countries, flat per seat, no Microsoft Calling Plan bill. Use our managed Ribbon SBC and skip the infrastructure entirely.

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countries · native CLI: 33
managed Ribbon · optional: SBC included
end-to-end encrypted: TLS / SRTP
inbound to Teams: < 200ms

Why bring outside trunking into Teams.

Microsoft Calling Plans are a fine default if you call three countries and have light volume. For outbound-heavy teams across multiple markets the maths flip fast.

Microsoft Calling Plans

The default Microsoft path.

~$8–$20 per user per month, plus bundled minutes that overage at per-minute rates
~12 countries supported with native local numbers — anything else needs a Direct Routing carrier anyway
No bring-your-own-number for many regions; porting in foreign numbers is painful
Outbound caller-ID customisation limited

UnlimCall via Direct Routing

Same Teams client. Carrier you control.

Flat per seat — unlimited outbound included, no per-minute math
Native local numbers in 33 countries — UK, EU, US, CA, AU, plus 28 more
STIR/SHAKEN attestation A on US/CA outbound — answer rates hold up
Per-user caller-ID override — pick which number any agent presents
Port your existing numbers in — no service interruption

How Direct Routing wires together.

Teams uses a certified Session Border Controller as the demarcation point between your tenant and any outside SIP trunk. We provide the trunk and, if you want, the SBC too — we operate a managed Ribbon SBC so you can skip the infrastructure entirely. Microsoft signs off in PowerShell. End to end, this is a one-day setup.

We provide

SIP edge with TLS/SRTP
Per-trunk credentials
Managed Ribbon SBC (optional)
Local numbers + porting
STIR/SHAKEN US/CA signing
E911/E112 routing

You provide

Microsoft 365 tenant
Teams Phone licenses
Your own certified SBC — if you don't use ours
Tenant admin PowerShell access
LIS / dispatchable-location records

Microsoft provides

Phone System (Teams Phone)
Direct Routing endpoint
Per-user number assignment
Teams clients + call routing
Tenant admin centre + LIS

Three ways to handle the SBC.

The fastest path: use our managed Ribbon SBC — we operate it, you pair it to your tenant in PowerShell. Or bring your own from Microsoft's certified list, or rent one from a third-party hosted SBC service.

Vendor	Models	Hosting	Status
UnlimCall managed RibbonRecommended	We operate the SBC for you — pair it to your tenant, we run it	Managed by us	Live
AudioCodes	Mediant 500 / 800 / 1000 / 4000 / VE	Self-hosted	Tested
Ribbon	SBC SWe / 1000 / 2000 / 5000	Self-hosted	Tested
AnyNode	TE-SYSTEMS AnyNode software SBC	Self-hosted	Tested
Oracle	Acme Packet SBC	Self-hosted	Tested
Cisco	CUBE (Unified Border Element)	Self-hosted	Tested
Sangoma	SBC + NetBorder	Self-hosted	Tested

Running something else certified by Microsoft? It almost certainly works — talk to us before you order seats and we will confirm against your specific SBC firmware.

Six steps to live calls.

Roughly one working day end-to-end if you have an SBC ready. Half a day with a hosted SBC. We pair on a call for the PowerShell step if you want a second set of eyes.

1
Confirm Microsoft 365 licensing on your tenant
Each user who will place / receive PSTN calls needs a Teams Phone license. Bundled into E5; add-on SKU for E1 / E3 / Business plans. Teams Phone Standard is the minimum.
Microsoft Admin Center · ~5 min
2
Provision UnlimCall seats + numbers
Sign up at app.unlimcall.com, pick one or more countries, buy seats (one per concurrent Teams call you expect), and order local numbers. We hand you the SIP host, per-trunk credentials, and the FQDN of our regional edge.
~10 min
3
Pick an SBC path
Three options. (1) Easiest: use our managed Ribbon SBC — we operate the box, you do nothing except pair it to your tenant. (2) Bring your own — AudioCodes / Ribbon / AnyNode / Oracle / Cisco / Sangoma all certified by Microsoft, you handle the FQDN + TLS cert + ongoing patching. (3) Use a third-party hosted SBC service. Most SMB customers pick path 1.
~30 min on our SBC · half-day if BYO
4
Pair the SBC with your Microsoft 365 tenant
Run the PowerShell snippet below: New-CsOnlinePSTNGateway points your SBC FQDN at Microsoft. Create a voice route, PSTN usage, voice routing policy. Microsoft acknowledges your SBC after the first OPTIONS exchange — usually within 30 seconds.
~15 min
5
Assign numbers to Teams users
Set-CsPhoneNumberAssignment with PhoneNumberType DirectRouting hands an UnlimCall number to a specific user. Grant the voice routing policy to that user. They see the dial-pad in Teams the next time they refresh.
~2 min per user · bulk-scriptable
6
Test from one user, then roll out
Test outbound to a mobile + inbound from a mobile. Verify caller ID presents correctly, audio is clean both ways, and DTMF works (IVR navigation). Once one user is solid, batch-assign the rest of the floor.
Same day

The trunk spec your SBC needs.

Teams Direct Routing is stricter than a plain SIP trunk — TLS + SRTP required, public CA cert on your SBC FQDN, specific codec set. The values below are what your SBC will be configured against.

unlimcall trunk · Teams Direct Routing profile

SIP host
sip-<region>.unlimcall.com— TLS only — Teams requires encrypted signalling
Transport
TLS 1.2+— TCP/UDP not accepted by Teams Direct Routing
Signalling port
5061
Media
SRTP (AES-256)— Mandatory — non-SRTP rejected by Teams
Codecs
SILK · G.722 · G.711 (μ-law / a-law) · OPUS— SILK + G.722 used inside Teams; G.711 transcoded at the SBC
DTMF
RFC 4733— In-band DTMF disabled by Teams
Authentication
IP whitelist (your SBC public IP) + per-trunk credential
TLS cert validation
Public CA (Let’s Encrypt, DigiCert, Sectigo)— Self-signed certs are rejected by both ends — your SBC FQDN must have a valid public cert

PowerShell pairing — copy, edit, run.

This is the Microsoft 365 side of the pairing. Replace sbc.contoso.com with your SBC's public FQDN and [email protected] with the first user you want to test on.

Microsoft Teams · PowerShell

run as tenant admin

# 1. Connect to your tenant
Connect-MicrosoftTeams

# 2. Register your SBC as a PSTN gateway
New-CsOnlinePSTNGateway `
  -Fqdn sbc.contoso.com `
  -SipSignalingPort 5061 `
  -ForwardCallHistory $true `
  -ForwardPai $true `
  -MediaBypass $false `
  -Enabled $true

# 3. Define a PSTN usage
Set-CsOnlinePstnUsage -Identity Global -Usage @{Add="UnlimCall"}

# 4. Create a voice route — match everything, send to your SBC
New-CsOnlineVoiceRoute `
  -Identity "UnlimCallRoute" `
  -NumberPattern ".*" `
  -OnlinePstnGatewayList sbc.contoso.com `
  -OnlinePstnUsages "UnlimCall" `
  -Priority 1

# 5. Build a voice routing policy
New-CsOnlineVoiceRoutingPolicy `
  -Identity "UnlimCallPolicy" `
  -OnlinePstnUsages "UnlimCall"

# 6. Assign the policy + a number to your first test user
Grant-CsOnlineVoiceRoutingPolicy `
  -Identity [email protected] `
  -PolicyName "UnlimCallPolicy"

Set-CsPhoneNumberAssignment `
  -Identity [email protected] `
  -PhoneNumber +12025550100 `
  -PhoneNumberType DirectRouting

Numbers shown are examples. Your portal exposes the exact E.164 numbers attached to your account. For bulk user assignment we'll hand you a parametrised script — mail [email protected].

What we cover. What stays on you.

On us

SIP trunk with TLS + SRTP, IP-locked to your SBC
Managed Ribbon SBC — we run the box, you skip the infrastructure
Local numbers in 33 markets · port-in supported
STIR/SHAKEN attestation A on US & CA outbound
E911 (US/CA) / E112 (EU/UK) emergency routing
SBC pairing assistance — we'll join a call
Carrier-side troubleshooting if anything breaks

On you

Microsoft 365 tenant + Teams Phone licensing
The SBC — or use ours, then skip this
Public FQDN + TLS cert — ditto, ours comes pre-certified
Per-user phone-number assignment in Teams admin
LIS / dispatchable-location records for E911 accuracy
Tenant-admin PowerShell access for the pairing

FAQ.

Do I need to provision my own SBC?+

No. We operate a managed Ribbon SBC and can pair it to your Microsoft 365 tenant directly — you do nothing on the infrastructure side. We hand you an FQDN, you paste it into the PowerShell pairing snippet, and you're wired up. Customers who want full control can still bring their own (AudioCodes / Ribbon / AnyNode / Oracle / Cisco / Sangoma all certified). Most SMB customers pick the managed path; teams with strict internal infra requirements bring their own.

Do I need to be on Microsoft Operator Connect?+

No. Direct Routing is the path you can run today — it just needs an SBC. Operator Connect is a separate Microsoft program where pre-integrated carriers show up directly inside the Teams admin centre with no SBC at all. We are applying for Operator Connect; meanwhile every UnlimCall customer using Teams runs Direct Routing.

What about Microsoft Calling Plans — do I keep them?+

You can run both side-by-side, but most customers drop Calling Plans entirely after migrating. Calling Plans bill per user (~$8–20/mo each) plus bundled minutes that overage at per-minute rates, and the country list is short. UnlimCall is flat per seat across 33 markets — usually 60–80% cheaper for an outbound-heavy team.

E911 / emergency services — how is that handled?+

For US/CA numbers we register the service address you provide in the portal with the appropriate Emergency Service Routing carrier (Bandwidth or Intrado). 911 dials from Teams route through us, hit ESRP, get the right PSAP based on the dispatchable location. For EU/UK we route 112/999 to the regional emergency authority per market. You configure the dispatchable location per user in the Teams Admin Centre (LIS).

Will media bypass work?+

Media bypass (Teams client ↔ SBC direct, skipping the Microsoft media path) is supported by us but is a Teams-side feature you enable on the PSTN gateway. We don't require it; if your SBC supports media bypass and your customers are geographically close to your SBC, you can enable it for ~30 ms lower one-way audio latency.

How many concurrent calls does the trunk support?+

Each UnlimCall seat = 1 concurrent outbound channel. Buy seats to match your peak concurrency — 50-agent team, peak 20 simultaneous calls, you want 20+ seats. We test SBCs in production at 1,000+ concurrent calls; the limit on your side is your SBC sizing.

Caller-ID — can I show a UK number from a UK Teams user even though the trunk is in EU Central?+

Yes. Caller ID is set per user in the Teams Admin Centre. The trunk region is about audio latency, not number presentation. A user in London with a UK number will show the UK number regardless of which UnlimCall edge POP carries their audio.

Inbound calls — how do they reach Teams?+

We route the PSTN call to your SBC over TLS/SRTP, the SBC forwards to Microsoft Phone System, Microsoft rings the assigned Teams user. End-to-end latency typically <200 ms one-way in our covered regions.

What if my SBC is on the AudioCodes hosted service or other SBCaaS?+

Works identically. The pairing instructions are the same — point us at your hosted SBC's FQDN; we whitelist its public IP; the customer-side admin runs the same Teams PowerShell against the hosted SBC FQDN.

Ready to wire UnlimCall into Teams?

Book a 30-minute session with a Teams Direct Routing specialist. We'll size your seats, recommend an SBC path, and pair on the PowerShell when you're ready.

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