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Microsoft Teams Direct Routing

Connect Microsoft Teams Phone to PSTN through Ribbon SBC and SIPPER's Pure VoIP Network. Keep your Thai numbers, avoid per-user Calling Plan fees, and get enterprise-grade voice quality on Teams.

TEAMS PHONE FOR ENTERPRISE

Direct Routing puts you in control

Direct Routing lets you connect Microsoft Teams Phone to a PSTN provider of your choice instead of buying Microsoft Calling Plans. SIPPER provides Microsoft-certified Ribbon SBC SWe Edge, SIP Trunks on a Pure VoIP Network with direct interconnection to NT (National Telecom) and True Corporation, plus Thai DID numbers.

Your Teams users make and receive PSTN calls with enterprise-grade voice quality at a lower cost and with more control than Microsoft Calling Plans, especially for organizations with 50 or more users.

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Overview

What is Microsoft Teams Direct Routing

Direct Routing connects Teams Phone to a carrier of your choice instead of Microsoft Calling Plans. SIPPER provides Microsoft-certified Ribbon SBC, SIP Trunks on a Pure VoIP Network, and Thai DID numbers all in one place.

Why 01 / SBC

Microsoft-certified Ribbon SBC

Microsoft-certified Ribbon SBC SWe Edge managed by SIPPER. Supports up to 2,000 concurrent calls, 1:1 Active-Standby HA with Mid-call Failover. Handles SIP-to-Teams protocol conversion, media transcoding, topology hiding, and DoS / DDoS protection.

Why 02 / Network

SIPPER SIP Trunks

Calls route through SIPPER's Pure VoIP Network, a voice-only infrastructure with no traffic mixing. Direct interconnection to carriers NT (National Telecom) and True Corporation. Thai DID numbers with bundled calling minutes in the package.

Why 03 / Numbers

Keep your existing numbers

Port your existing Thai numbers to SIPPER. We coordinate with carriers NT and True end-to-end. Most ports complete within 5 to 10 business days. Your customers, partners, and staff dial the same numbers as before.

Key Features

Everything you need for Teams calling

A complete enterprise feature set for connecting Teams to the PSTN, from security to hybrid PBX.

No per-user Calling Plan fees

Microsoft Calling Plans charge per user per month. Direct Routing uses concurrent channels instead, pay for capacity, not headcount. Saves 30 to 50% for organizations with 50+ users compared to Microsoft Calling Plans.

Thai DID Numbers

Bangkok and provincial numbers via direct interconnection to carriers NT and True. Port existing numbers or activate new ones. Full CLI pass-through with Flexible Caller ID, including Mobile CLI for higher answer rates.

End-to-end Encryption and Security

TLS for signaling, SRTP for media via SDES key exchange. Ribbon SBC adds Topology Hiding (B2BUA), DoS / DDoS protection, rate limiting, and rogue RTP filtering. Enterprise-grade security from Teams client to carrier network.

High Availability and Mid-call Failover

Ribbon SBC SWe Edge in 1:1 Active-Standby pairs supporting 2,000 concurrent calls. Mid-call Failover keeps active calls connected even during hardware failure. Multi-carrier failover between NT and True. 99.99% SLA.

Hybrid PBX and Teams

Run Direct Routing alongside your existing PBX. Some users on Teams, others on Yeastar or 3CX. Share the same SIP Trunk and DID numbers through Ribbon SBC. Migrate users in waves at your own pace.

Media Bypass

When enabled, media flows directly between Teams client and SIPPER's SBC, bypassing Microsoft cloud. Reduces latency and improves call quality. Especially beneficial for users in Thailand calling Thai numbers.

Who is it for

Teams Direct Routing is right for you if

Direct Routing is the PSTN connectivity model organizations choose when they want control over voice infrastructure and cost.

Already on Microsoft 365

You have Microsoft 365 E5 (or E3 + Phone System add-on) and want to add PSTN calling without Microsoft Calling Plans. Direct Routing gives you more control and is usually cheaper.

Migrating from a legacy PBX

Moving from on-premise PBX to Teams for calling and collaboration. SIPPER handles voice connectivity so you can focus on the Teams rollout.

Multi-site or international offices

Organizations with offices across Thailand or abroad. Centralize voice infrastructure on a single SBC and trunk, with regional DID numbers in each location.

All Capabilities

Complete Direct Routing feature set

Security and Voice Quality

TLS / SRTP Encryption (SDES)
Topology Hiding (B2BUA)
DoS / DDoS Protection
SBC Active-Standby (HA)
Mid-call Failover
G.711 / G.722 / G.729 / Opus Codecs
DTMF (RFC 2833)
Media Bypass Support

Teams Integration

CLI Pass-through (Caller ID)
Flexible CLI / Mobile CLI
E.164 Number Formatting
Teams Auto Attendant
Teams Call Queue
Teams Voicemail Integration
Teams Resource Accounts
Hybrid PBX and Teams
Call Quality Dashboard
CDR and Analytics
Location-based Routing

How It Works

From Teams to the phone network and beyond

SIPPER manages the entire infrastructure. You only need Microsoft 365 with a Phone System license. We handle the SBC, trunk, and carrier connectivity.

Step 1: SIPPER provisions the Ribbon SBC

We provision a dedicated Ribbon SBC SWe Edge instance for your tenant with 1:1 Active-Standby HA. The SBC is connected to Microsoft Teams via Microsoft 365 admin portal. SIPPER manages all configuration including TLS certificates, SIP profiles, codecs (G.711 / G.722 / G.729 / Opus), security policies, and topology hiding.

Step 2: Activate or port numbers

Choose new Thai DID numbers or port existing ones from your current provider. Numbers are activated through direct interconnection with NT and True carriers and configured on the SBC. SIPPER manages the carrier-side porting process end-to-end. Most ports complete within 5 to 10 business days.

Step 3: Assign numbers and start calling

Assign numbers to Teams users in the Microsoft 365 admin center. Users can make and receive PSTN calls from Teams desktop, mobile, or web client immediately. SIPPER configures Auto Attendant, Call Queue, and Resource Accounts as needed. 24/7 NOC monitoring tracks call quality from day one.

Hybrid PBX and Teams: migrate in waves

You don't have to migrate all users to Teams at once. SIPPER's Ribbon SBC routes calls to both Teams and your existing PBX (Yeastar, 3CX, Asterisk, or legacy systems) over the same SIP Trunk. Share DID numbers so you can move users group by group on the same voice infrastructure.

FAQ

Frequently asked questions about Teams Direct Routing

You need Microsoft 365 E5 (which includes Phone System) or Microsoft 365 E3 + Phone System add-on. Microsoft Calling Plans are NOT required, Direct Routing uses SIPPER's SIP Trunks instead.

Microsoft Calling Plans charge per user per month with Microsoft as the carrier. Direct Routing lets you choose your own carrier (SIPPER) and uses concurrent channels instead of per-user pricing. Usually cheaper for 50+ user organizations and provides more control.

No. SIPPER provides and manages the Ribbon SBC as a service. You don't buy, host, or maintain SBC hardware or software. The SBC is included in the Direct Routing service.

Yes. SIPPER handles porting from your current provider. Most ports complete within 5 to 10 business days with minimal disruption. Your customers and partners dial the same numbers as before.

Yes. SIPPER supports hybrid deployments where some users are on Teams while others remain on Yeastar or 3CX PBX. Both platforms share the same SIP Trunk and numbers through Ribbon SBC.

Calls route through SIPPER's Pure VoIP Network, a voice-only network with direct connectivity to NT and True carriers and no traffic mixing. Ribbon SBC supports G.711, G.722 (wideband HD), G.729, and Opus with GPU-accelerated transcoding. Combined with mid-call failover and 24/7 NOC, this delivers enterprise-grade voice quality.

Media Bypass lets media flow directly between Teams client and SIPPER's SBC, bypassing Microsoft cloud media processors. This reduces latency and improves call quality, especially for users in Thailand calling Thai numbers. SIPPER configures Media Bypass as part of the Direct Routing setup when your network topology supports it.

Operator Connect is a Microsoft-managed marketplace where carriers connect to Teams through Microsoft's infrastructure. Direct Routing connects an SBC directly to Teams, giving you more control over routing, failover, and hybrid PBX deployments. SIPPER uses Direct Routing because it supports hybrid PBX + Teams, custom call flows, and direct NT / True interconnection for consistent call quality.

Add PSTN calling to your Microsoft Teams

Tell us about your Microsoft 365 setup, user count, and current phone system. We will design a Direct Routing deployment that fits your organization.