diff --git a/src/main/java/de/neemann/digital/analyse/ModelAnalyser.java b/src/main/java/de/neemann/digital/analyse/ModelAnalyser.java
index a37a94f8e..458b2f1cd 100644
--- a/src/main/java/de/neemann/digital/analyse/ModelAnalyser.java
+++ b/src/main/java/de/neemann/digital/analyse/ModelAnalyser.java
@@ -155,14 +155,17 @@ public class ModelAnalyser {
                     SplitPinString pins = SplitPinString.create(s);
 
                     final ObservableValues spOutputs = sp.getOutputs();
+                    String name = s.getName();
+                    if (!name.contains("_"))
+                        name += "_";
                     for (int i = spOutputs.size() - 1; i >= 0; i--)
-                        outputs.add(new Signal(s.getName() + i, spOutputs.get(i)).setPinNumber(pins.getPin(i)));
+                        outputs.add(new Signal(name + i, spOutputs.get(i)).setPinNumber(pins.getPin(i)));
 
                     s.getValue().fireHasChanged();
 
                     ArrayList<String> names = new ArrayList<>(bits);
                     for (int i = 0; i < bits; i++)
-                        names.add(s.getName() + i);
+                        names.add(name + i);
 
                     modelAnalyzerInfo.addOutputBus(s.getName(), names);
 
@@ -194,10 +197,13 @@ public class ModelAnalyser {
 
                     SplitPinString pins = SplitPinString.create(s);
                     ObservableValues.Builder builder = new ObservableValues.Builder();
+                    String name = s.getName();
+                    if (!name.contains("_"))
+                        name += "_";
                     for (int i = bits - 1; i >= 0; i--) {
-                        ObservableValue o = new ObservableValue(s.getName() + i, 1);
+                        ObservableValue o = new ObservableValue(name + i, 1);
                         builder.add(o);
-                        inputs.add(new Signal(s.getName() + i, o).setPinNumber(pins.getPin(i)));
+                        inputs.add(new Signal(name + i, o).setPinNumber(pins.getPin(i)));
                     }
                     final ObservableValues inputsList = builder.reverse().build();
                     sp.setInputs(inputsList);
diff --git a/src/test/java/de/neemann/digital/analyse/ModelAnalyserTest.java b/src/test/java/de/neemann/digital/analyse/ModelAnalyserTest.java
index ad17e18ac..33d31a540 100644
--- a/src/test/java/de/neemann/digital/analyse/ModelAnalyserTest.java
+++ b/src/test/java/de/neemann/digital/analyse/ModelAnalyserTest.java
@@ -188,8 +188,8 @@ public class ModelAnalyserTest extends TestCase {
         checkTable(tt.getResult("Q_0^{n+1}"), one, zero, one, zero);
         checkTable(tt.getResult("Q_1^{n+1}"), zero, one, one, zero);
 
-        assertEquals("Y1", tt.getResultName(2));
-        assertEquals("Y0", tt.getResultName(3));
+        assertEquals("Y_1", tt.getResultName(2));
+        assertEquals("Y_0", tt.getResultName(3));
         final BoolTable y1 = tt.getResult(2);
         final BoolTable y0 = tt.getResult(3);
         for (int i = 0; i < 4; i++) {
@@ -205,10 +205,10 @@ public class ModelAnalyserTest extends TestCase {
         checkIdent(tt);
 
         TreeMap<String, String> p = tt.getModelAnalyzerInfo().getPins();
-        assertEquals("i1", p.get("A0"));
-        assertEquals("i2", p.get("A1"));
-        assertEquals("o1", p.get("B0"));
-        assertEquals("o2", p.get("B1"));
+        assertEquals("i1", p.get("A_0"));
+        assertEquals("i2", p.get("A_1"));
+        assertEquals("o1", p.get("B_0"));
+        assertEquals("o2", p.get("B_1"));
     }
 
     // test with non zero default values set
@@ -219,8 +219,8 @@ public class ModelAnalyserTest extends TestCase {
     }
 
     private void checkIdent(TruthTable tt) {
-        checkTable(tt.getResult("B1"), zero, zero, one, one);
-        checkTable(tt.getResult("B0"), zero, one, zero, one);
+        checkTable(tt.getResult("B_1"), zero, zero, one, one);
+        checkTable(tt.getResult("B_0"), zero, one, zero, one);
     }
 
     private void checkTable(BoolTable table, ThreeStateValue... expected) {
@@ -270,11 +270,11 @@ public class ModelAnalyserTest extends TestCase {
         ModelAnalyserInfo mai = new ModelAnalyser(model).analyse().getModelAnalyzerInfo();
 
         assertEquals(2, mai.getInputBusMap().size());
-        checkBus(mai.getInputBusMap(), "A", "A0", "A1", "A2", "A3");
-        checkBus(mai.getInputBusMap(), "B", "B0", "B1", "B2", "B3");
+        checkBus(mai.getInputBusMap(), "A", "A_0", "A_1", "A_2", "A_3");
+        checkBus(mai.getInputBusMap(), "B", "B_0", "B_1", "B_2", "B_3");
 
         assertEquals(1, mai.getOutputBusMap().size());
-        checkBus(mai.getOutputBusMap(), "S", "S0", "S1", "S2", "S3");
+        checkBus(mai.getOutputBusMap(), "S", "S_0", "S_1", "S_2", "S_3");
     }
 
     private void checkBus(HashMap<String, ArrayList<String>> busMap, String name, String... names) {