05 · PSTN connectivity
This is the option when you still own trunks, a PBX, analog devices, or a contact-center SBC.
You pair an SBC FQDN on a verified domain, present a public certificate, signal TLS to sip.pstnhub.microsoft.com and its sip2 and sip3 partners on port 5061, and allow media UDP 3478–3481 and 49152–53247. Firewall rules must allow the published IP ranges, not only today’s DNS answer. GCC High and DoD use different proxy names.
Users need Teams and Teams Phone, homed online, not in Islands mode. Budget at least two media ports per concurrent call. Microsoft does not support media re-targeting mid-call. Codecs include SILK, G.711, G.722, G.729, and AMR-WB only when bypass is off.
Direct Routing is your certified SBC, TLS on 5061 to the PSTN hubs, and a voice route on a Teams Phone user.
5061 to the three commercial proxies, media on those UDP ranges, certificate name matches the FQDN, user has a route.
If it fails: 5061 is open, media is not, and both sides hear silence.
Which description of Media ports for Direct Routing is accurate?
UDP 3478–3481 and 49152–53247 between the SBC and the media processors, unless media bypass keeps the media off that path. People open 5061 and forget media, so signaling works and audio does not. Source: https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan accessed 2026-10-14.
A colleague reports: Calls connect and both sides hear silence. Where do you start?
Calls connect and both sides hear silence. Budget at least two media ports per concurrent call on the SBC. Source: https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan accessed 2026-10-14.
Which description of Media re-targeting is accurate?
Microsoft does not support changing the media target in the middle of an active Direct Routing call. A clever SBC feature that moves media mid-call will not be a supported troubleshooting step. Source: https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan accessed 2026-10-14.
Around the call: compliance recording, workforce management, emergency location, analytics, CRM screen pop, and an agent with a human escape. Each one has its own failure.
5061 is open, media is not, and both sides hear silence.
Cisco CUBE is one of the SBC families named in this lab’s certification lesson. A certified release can be the Direct Routing SBC between Unified CM and Teams.
The tenant still needs a verified domain on the SBC FQDN, and the user still needs Teams Phone. The studio translator does not open a live AXL session. Confirm the current certified release before you build.
Teams Phone and Webex Calling are separate clouds. This lab does not describe a feature that registers a Webex Calling user into a Teams tenant.
A number move is usually a carrier port, a certified SBC, or a meetings interop product. Confirm before relying.
Unified CCE stays the ACD until you migrate it. Microsoft’s contact-center articles name Connect, Extend, and Unify. They do not name a UCCE connector in the notes this lab cites.
Voice into Teams is still Direct Routing or Operator Connect. The routing script stays on the contact-center product you bought. Confirm the vendor’s current model. Source: https://learn.microsoft.com/en-us/microsoftteams/teams-contact-center.
Copilot Studio, Azure Communication Services, and Graph are later tracks in this lab. Treat any uncited limit as confirm before relying.
Opened 2026-10. A row marked confirm did not open. Wikipedia is background. The Teams blog row is the community index.
