diff --git a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
index f6414bf2..c5e23c52 100644
--- a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
+++ b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
@@ -210,7 +210,7 @@ BACNET_POLARITY Binary_Output_Polarity(
     return polarity;
 }
 
-static void Binary_Output_Out_Of_Service_Set(
+void Binary_Output_Out_Of_Service_Set(
     uint32_t instance,
     bool flag)
 {