diff --git a/pydyf/__init__.py b/pydyf/__init__.py
index d268aeb..d73e369 100755
--- a/pydyf/__init__.py
+++ b/pydyf/__init__.py
@@ -17,12 +17,12 @@ def _to_bytes(item):
         return item.data
     elif isinstance(item, float):
         if item.is_integer():
-            return f'{int(item):d}'.encode()
+            return f'{int(item):d}'.encode('ascii')
         else:
-            return f'{item:f}'.encode()
+            return f'{item:f}'.encode('ascii')
     elif isinstance(item, int):
-        return f'{item:d}'.encode()
-    return str(item).encode()
+        return f'{item:d}'.encode('ascii')
+    return str(item).encode('ascii')
 
 
 class Object:
diff --git a/tests/test_pydyf.py b/tests/test_pydyf.py
index 22ffe9e..87d9763 100644
--- a/tests/test_pydyf.py
+++ b/tests/test_pydyf.py
@@ -700,3 +700,9 @@ def test_text():
         __________
         __________
     ''')
+
+
+def test_string_encoding():
+    assert pydyf.String('abc').data == b'(abc)'
+    assert pydyf.String('déf').data == b'<feff006400e90066>'
+    assert pydyf.String('♡').data == b'<feff2661>'