diff --git a/src/fastcs/transport/epics/ca/util.py b/src/fastcs/transport/epics/ca/util.py
index 66af0cd2..312252ee 100644
--- a/src/fastcs/transport/epics/ca/util.py
+++ b/src/fastcs/transport/epics/ca/util.py
@@ -92,6 +92,9 @@ def _verify_in_datatype(_, value):
                     return value in datatype.names
 
                 arguments["validate"] = _verify_in_datatype
+        case Bool():
+            arguments["ZNAM"] = "False"
+            arguments["ONAM"] = "True"
 
     return arguments