diff --git a/NEXT.md b/NEXT.md
index 29d2ad1..8c64061 100644
--- a/NEXT.md
+++ b/NEXT.md
@@ -1,6 +1,7 @@
 # NEXT_STEPS
 
 ## Aktive Aufgaben (priorisiert)
+- [x] [#26] patchfelder haben natürlich auf den gleichen port eine feste verdrahtung und dann ein patchkabel zum switch, bei wand buchsen muss das auch erlaubt sein
 - [x] [#24] infrastruktur stockerkkarte zoomen wird die grundrisskarten overlay nicht mitgezoomt
 - [x] [#23] netzwerkdosen haben nur port 1 und brauche in den auswahlen nicht mit port 1 angezeigt zu werden
 - [x] [#22] für neue verbindungen nur ports anbieten die noch keine verbingung haben
diff --git a/app/api/connections.php b/app/api/connections.php
index d2c2ff5..c67d792 100644
--- a/app/api/connections.php
+++ b/app/api/connections.php
@@ -90,6 +90,87 @@ function isTopologyPairAllowed(string $typeA, string $typeB): bool
     return true;
 }
 
+function buildEndpointUsageMap($sql, int $excludeConnectionId = 0): array
+{
+    $usage = [
+        'device' => [],
+        'module' => [],
+        'outlet' => [],
+        'patchpanel' => [],
+    ];
+
+    $rows = $sql->get(
+        "SELECT id, port_a_type, port_a_id, port_b_type, port_b_id
+         FROM connections
+         WHERE id <> ?",
+        'i',
+        [$excludeConnectionId]
+    );
+
+    $track = static function (string $endpointType, int $endpointId, string $otherType) use (&$usage): void {
+        if ($endpointId <= 0 || !isset($usage[$endpointType])) {
+            return;
+        }
+        if (!isset($usage[$endpointType][$endpointId])) {
+            $usage[$endpointType][$endpointId] = [
+                'total' => 0,
+                'fixed' => 0,
+                'patch' => 0,
+            ];
+        }
+
+        $usage[$endpointType][$endpointId]['total']++;
+        if (in_array($endpointType, ['outlet', 'patchpanel'], true)) {
+            if (in_array($otherType, ['outlet', 'patchpanel'], true)) {
+                $usage[$endpointType][$endpointId]['fixed']++;
+            } elseif (in_array($otherType, ['device', 'module'], true)) {
+                $usage[$endpointType][$endpointId]['patch']++;
+            }
+        }
+    };
+
+    foreach ((array)$rows as $row) {
+        $typeA = normalizeEndpointType((string)($row['port_a_type'] ?? ''));
+        $typeB = normalizeEndpointType((string)($row['port_b_type'] ?? ''));
+        $idA = (int)($row['port_a_id'] ?? 0);
+        $idB = (int)($row['port_b_id'] ?? 0);
+        if ($typeA === null || $typeB === null) {
+            continue;
+        }
+        $track($typeA, $idA, $typeB);
+        $track($typeB, $idB, $typeA);
+    }
+
+    return $usage;
+}
+
+function validateEndpointCapacity(array $usage, string $endpointType, int $endpointId, string $otherType, string $label): ?string
+{
+    if ($endpointId <= 0) {
+        return null;
+    }
+
+    $stats = $usage[$endpointType][$endpointId] ?? ['total' => 0, 'fixed' => 0, 'patch' => 0];
+    if ((int)$stats['total'] <= 0) {
+        return null;
+    }
+
+    if (in_array($endpointType, ['outlet', 'patchpanel'], true)) {
+        if ((int)$stats['total'] >= 2) {
+            return $label . ' hat bereits die maximale Anzahl von 2 Verbindungen';
+        }
+        if (in_array($otherType, ['outlet', 'patchpanel'], true) && (int)$stats['fixed'] >= 1) {
+            return $label . ' hat bereits eine feste Verdrahtung';
+        }
+        if (in_array($otherType, ['device', 'module'], true) && (int)$stats['patch'] >= 1) {
+            return $label . ' hat bereits ein Patchkabel';
+        }
+        return null;
+    }
+
+    return $label . ' ist bereits in Verwendung';
+}
+
 function loadConnections($sql): void
 {
     $contextType = strtolower(trim((string)($_GET['context_type'] ?? 'all')));
@@ -226,9 +307,20 @@ function saveConnection($sql): void
     $mode = isset($data['mode']) ? (string)$data['mode'] : null;
     $comment = isset($data['comment']) ? (string)$data['comment'] : null;
 
-    if (!empty($data['id'])) {
-        $id = (int)$data['id'];
-        $existing = $sql->single('SELECT id FROM connections WHERE id = ?', 'i', [$id]);
+    $connectionId = !empty($data['id']) ? (int)$data['id'] : 0;
+    $usage = buildEndpointUsageMap($sql, $connectionId);
+    $capacityErrorA = validateEndpointCapacity($usage, $portAType, $portAId, $portBType, 'Port an Endpunkt A');
+    if ($capacityErrorA !== null) {
+        jsonError($capacityErrorA, 409);
+    }
+    $capacityErrorB = validateEndpointCapacity($usage, $portBType, $portBId, $portAType, 'Port an Endpunkt B');
+    if ($capacityErrorB !== null) {
+        jsonError($capacityErrorB, 409);
+    }
+
+    if ($connectionId > 0) {
+        $id = $connectionId;
+        $existing = $sql->single('SELECT id FROM connections WHERE id = ?', 'i', [$connectionId]);
         if (!$existing) {
             jsonError('Verbindung existiert nicht', 404);
         }
diff --git a/app/modules/connections/edit.php b/app/modules/connections/edit.php
index 68006a6..84a14a3 100644
--- a/app/modules/connections/edit.php
+++ b/app/modules/connections/edit.php
@@ -46,7 +46,7 @@ $endpointOptions = [
     'patchpanel' => [],
 ];
 
-$occupiedByType = [
+$occupiedStatsByType = [
     'device' => [],
     'module' => [],
     'outlet' => [],
@@ -62,18 +62,24 @@ $occupiedRows = $sql->get(
 foreach ((array)$occupiedRows as $row) {
     $typeA = $normalizePortType((string)($row['port_a_type'] ?? ''));
     $idA = (int)($row['port_a_id'] ?? 0);
-    if ($idA > 0 && isset($occupiedByType[$typeA])) {
-        $occupiedByType[$typeA][$idA] = true;
+    if ($idA > 0 && isset($occupiedStatsByType[$typeA])) {
+        if (!isset($occupiedStatsByType[$typeA][$idA])) {
+            $occupiedStatsByType[$typeA][$idA] = ['total' => 0];
+        }
+        $occupiedStatsByType[$typeA][$idA]['total']++;
     }
 
     $typeB = $normalizePortType((string)($row['port_b_type'] ?? ''));
     $idB = (int)($row['port_b_id'] ?? 0);
-    if ($idB > 0 && isset($occupiedByType[$typeB])) {
-        $occupiedByType[$typeB][$idB] = true;
+    if ($idB > 0 && isset($occupiedStatsByType[$typeB])) {
+        if (!isset($occupiedStatsByType[$typeB][$idB])) {
+            $occupiedStatsByType[$typeB][$idB] = ['total' => 0];
+        }
+        $occupiedStatsByType[$typeB][$idB]['total']++;
     }
 }
 
-$isEndpointAllowed = static function (string $type, int $id) use ($occupiedByType, $portAType, $portAId, $portBType, $portBId): bool {
+$isEndpointAllowed = static function (string $type, int $id) use ($occupiedStatsByType, $portAType, $portAId, $portBType, $portBId): bool {
     if ($id <= 0) {
         return false;
     }
@@ -83,7 +89,10 @@ $isEndpointAllowed = static function (string $type, int $id) use ($occupiedByTyp
     if ($type === $portBType && $id === $portBId) {
         return true;
     }
-    return empty($occupiedByType[$type][$id]);
+
+    $stats = $occupiedStatsByType[$type][$id] ?? ['total' => 0];
+    $maxConnections = in_array($type, ['outlet', 'patchpanel'], true) ? 2 : 1;
+    return (int)($stats['total'] ?? 0) < $maxConnections;
 };
 
 // Auto-heal: ensure each outlet has at least one selectable port.
diff --git a/app/modules/connections/save.php b/app/modules/connections/save.php
index 68faebb..e5daf5d 100644
--- a/app/modules/connections/save.php
+++ b/app/modules/connections/save.php
@@ -75,16 +75,26 @@ $otherConnections = $sql->get(
 );
 
 $endpointUsage = [];
-$trackUsage = static function (string $endpointType, int $endpointId) use (&$endpointUsage): void {
+$trackUsage = static function (string $endpointType, int $endpointId, string $otherType) use (&$endpointUsage): void {
     if ($endpointId <= 0) {
         return;
     }
     if (!isset($endpointUsage[$endpointType][$endpointId])) {
         $endpointUsage[$endpointType][$endpointId] = [
             'total' => 0,
+            'fixed' => 0,
+            'patch' => 0,
         ];
     }
     $endpointUsage[$endpointType][$endpointId]['total']++;
+
+    if (in_array($endpointType, ['outlet', 'patchpanel'], true)) {
+        if (in_array($otherType, ['outlet', 'patchpanel'], true)) {
+            $endpointUsage[$endpointType][$endpointId]['fixed']++;
+        } elseif (in_array($otherType, ['device', 'module'], true)) {
+            $endpointUsage[$endpointType][$endpointId]['patch']++;
+        }
+    }
 };
 
 foreach ((array)$otherConnections as $row) {
@@ -93,29 +103,42 @@ foreach ((array)$otherConnections as $row) {
     $idA = (int)($row['port_a_id'] ?? 0);
     $idB = (int)($row['port_b_id'] ?? 0);
 
-    $trackUsage($typeA, $idA);
-    $trackUsage($typeB, $idB);
+    $trackUsage($typeA, $idA, $typeB);
+    $trackUsage($typeB, $idB, $typeA);
 }
 
-$validateEndpointUsage = static function (string $endpointType, int $endpointId, string $label) use ($endpointUsage): ?string {
+$validateEndpointUsage = static function (string $endpointType, int $endpointId, string $otherType, string $label) use ($endpointUsage): ?string {
     if ($endpointId <= 0) {
         return null;
     }
 
-    $stats = $endpointUsage[$endpointType][$endpointId] ?? ['total' => 0];
+    $stats = $endpointUsage[$endpointType][$endpointId] ?? ['total' => 0, 'fixed' => 0, 'patch' => 0];
     if ((int)$stats['total'] <= 0) {
         return null;
     }
 
+    if (in_array($endpointType, ['outlet', 'patchpanel'], true)) {
+        if ((int)$stats['total'] >= 2) {
+            return $label . " hat bereits die maximale Anzahl von 2 Verbindungen";
+        }
+        if (in_array($otherType, ['outlet', 'patchpanel'], true) && (int)$stats['fixed'] >= 1) {
+            return $label . " hat bereits eine feste Verdrahtung";
+        }
+        if (in_array($otherType, ['device', 'module'], true) && (int)$stats['patch'] >= 1) {
+            return $label . " hat bereits ein Patchkabel";
+        }
+        return null;
+    }
+
     return $label . " ist bereits in Verwendung";
 };
 
-$errorA = $validateEndpointUsage($portAType, $portAId, 'Port an Endpunkt A');
+$errorA = $validateEndpointUsage($portAType, $portAId, $portBType, 'Port an Endpunkt A');
 if ($errorA !== null) {
     $errors[] = $errorA;
 }
 
-$errorB = $validateEndpointUsage($portBType, $portBId, 'Port an Endpunkt B');
+$errorB = $validateEndpointUsage($portBType, $portBId, $portAType, 'Port an Endpunkt B');
 if ($errorB !== null) {
     $errors[] = $errorB;
 }