{
  "room": "T05-R01-four-ways-to-reach-the-pstn.html",
  "lesson": "t05-four",
  "title": "Four ways to reach the PSTN",
  "checked": "2026-10",
  "sources": [
    {
      "title": "PSTN connectivity options",
      "url": "https://learn.microsoft.com/en-us/microsoftteams/pstn-connectivity",
      "kind": "learn",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": ""
    },
    {
      "title": "Plan Direct Routing",
      "url": "https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan",
      "kind": "learn",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": ""
    },
    {
      "title": "RFC 3261",
      "url": "https://www.rfc-editor.org/rfc/rfc3261",
      "kind": "rfc",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": ""
    },
    {
      "title": "Public switched telephone network",
      "url": "https://en.wikipedia.org/wiki/Public_switched_telephone_network",
      "kind": "wikipedia",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": "Wikipedia fallback for background. Confirm the vendor page before you change a tenant."
    },
    {
      "title": "Session Initiation Protocol",
      "url": "https://en.wikipedia.org/wiki/Session_Initiation_Protocol",
      "kind": "wikipedia",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": "Wikipedia fallback for background. Confirm the vendor page before you change a tenant."
    },
    {
      "title": "Microsoft Teams blog index",
      "url": "https://techcommunity.microsoft.com/category/microsoftteams/blog/microsoftteamsblog",
      "kind": "community",
      "lastChecked": "2026-10",
      "status": "ok",
      "note": "Community index for the Microsoft Teams blog. This is the index, not a claim that a post discusses this room."
    }
  ]
}