diff --git a/Coturn.md b/Coturn.md
new file mode 100644
index 00000000..be539739
--- /dev/null
+++ b/Coturn.md
@@ -0,0 +1,9 @@
+---
+kind: reference
+section: tool
+website: https://github.com/coturn/coturn
+lang: en
+---
+
+Coturn is a free open source implementation of TURN and STUN Server. The TURN Server is a VoIP media traffic NAT traversal server and gateway.
+
diff --git a/Interne Dienste.md b/Interne Dienste.md
index 5ba522c9..c0ce4b69 100644
--- a/Interne Dienste.md	
+++ b/Interne Dienste.md	
@@ -15,4 +15,5 @@ Interne Dienste für Mitarbeitende der Mint System:
 * [[Wiki Mint System]]
 * [[Chat Mint System]]
 * [[LLM Chat Mint System]]
-* [[N8N Mint System]]
\ No newline at end of file
+* [[N8N Mint System]]
+* [[TURN Mint System]]
\ No newline at end of file
diff --git a/N8N Mint System.md b/N8N Mint System.md
index 3a4b4796..441008c3 100644
--- a/N8N Mint System.md	
+++ b/N8N Mint System.md	
@@ -1,5 +1,4 @@
 ---
-title: N8N Mint System
 kind: reference
 website: https://n8n.mint-system.ch/
 section: infrastructure
diff --git a/N8N.md b/N8N.md
index 1a522af7..6bb4e80d 100644
--- a/N8N.md
+++ b/N8N.md
@@ -1,5 +1,4 @@
 ---
-title: N8N
 kind: reference
 section: tool
 website: https://n8n.io/
diff --git a/Nextcloud App Talk.md b/Nextcloud App Talk.md
index 1fa90eae..27f4774e 100644
--- a/Nextcloud App Talk.md	
+++ b/Nextcloud App Talk.md	
@@ -5,4 +5,36 @@ section: communication
 website: https://nextcloud.com/talk/
 ---
 
-Für den effizienten Betrieb braucht es einen Turn-Server.
+## ## TURN-Server
+
+Für den effizienten Betrieb braucht es einen TURN-Server wie [[TURN Mint System]].
+
+```mermaid
+sequenceDiagram
+  participant A as Browser A
+  participant NC as Nextcloud Talk<br/>cloud.mint-system.ch
+  participant TS as coturn<br/>turn.mint-system.ch
+  participant B as Browser B
+
+  A->>NC: Join call (HTTPS/WSS signaling)
+  B->>NC: Join call (HTTPS/WSS signaling)
+  NC->>NC: Generate time-limited TURN creds<br/>(HMAC with shared static-auth-secret)
+  NC-->>A: TURN URL + username/password
+  NC-->>B: TURN URL + username/password
+  A->>TS: STUN/TURN allocate request
+  B->>TS: STUN/TURN allocate request
+  Note over A,B: ICE tries direct P2P first
+  alt Direct path blocked by NAT/firewall
+    A->>TS: Media relay (UDP)
+    TS->>B: Media relay (UDP)
+  end
+  A->>NC: ICE candidates, call teardown
+  B->>NC: ICE candidates, call teardown
+```
+
+- **WSS** – WebSocket Secure – verschlüsselte WebSocket-Verbindung für das Signaling (Anrufaufbau, Steuerdaten).
+- **STUN** – Session Traversal Utilities for NAT – Server verrät dem Client seine öffentliche IP/Port.
+- **TURN** – Traversal Using Relays around NAT – Server leitet Medienverkehr weiter, wenn direkte Verbindung nicht klappt.
+- **NAT** – Network Address Translation – Mechanismus, mit dem sich mehrere Geräte eine öffentliche IP teilen.
+- **ICE** – Interactive Connectivity Establishment – Verfahren, das die beste Verbindungsmethode zwischen zwei Peers findet.
+- **UDP** – User Datagram Protocol – schnelles, verbindungsloses Transportprotokoll für Echtzeit-Medien.
\ No newline at end of file
diff --git a/TURN Mint System.md b/TURN Mint System.md
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index 00000000..de612af0
--- /dev/null
+++ b/TURN Mint System.md	
@@ -0,0 +1,6 @@
+---
+kind: reference
+section: infrastructure
+---
+
+Unter der Adresse `turn.mint-system.ch` läuft ein [[Coturn]] TURN-Server.
\ No newline at end of file
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