diff --git a/TiaCodegen-ts/src/Extensions/NaturalComparer.ts b/TiaCodegen-ts/src/Extensions/NaturalComparer.ts
index a11560d..cf49d0a 100644
--- a/TiaCodegen-ts/src/Extensions/NaturalComparer.ts
+++ b/TiaCodegen-ts/src/Extensions/NaturalComparer.ts
@@ -21,8 +21,10 @@ export class NaturalComparer {
                 }
                 if (vx !== vy) return vx < vy ? -1 : 1;
             } else {
-                const cmp = cx.toUpperCase().localeCompare(cy.toUpperCase());
-                if (cmp !== 0) return cmp;
+                // Ordinal comparison like char.ToUpperInvariant(cx).CompareTo(...) in the C# version
+                const ux = cx.toUpperCase();
+                const uy = cy.toUpperCase();
+                if (ux !== uy) return ux < uy ? -1 : 1;
                 i++;
                 j++;
             }
diff --git a/TiaCodegen-ts/tests/NaturalComparer.test.ts b/TiaCodegen-ts/tests/NaturalComparer.test.ts
new file mode 100644
index 0000000..63dd2b8
--- /dev/null
+++ b/TiaCodegen-ts/tests/NaturalComparer.test.ts
@@ -0,0 +1,15 @@
+import { NaturalComparer } from '../src/Extensions/NaturalComparer';
+
+describe('NaturalComparer', () => {
+    test('orders punctuation ordinally like the C# version', () => {
+        const names = ['GroupSignals.1_1.X', 'GroupSignals.1.X', 'GroupSignals.1_2.X', 'A_b', 'A.b', 'Ab', 'A-b', 'A b'];
+        names.sort((a, b) => new NaturalComparer().compare(a, b));
+        expect(names).toEqual(['A b', 'A-b', 'A.b', 'Ab', 'A_b', 'GroupSignals.1.X', 'GroupSignals.1_1.X', 'GroupSignals.1_2.X']);
+    });
+
+    test('compares numbers naturally and letters case-insensitively', () => {
+        const comparer = new NaturalComparer();
+        expect(comparer.compare('a2', 'a10')).toBeLessThan(0);
+        expect(comparer.compare('a', 'A')).toBe(0);
+    });
+});