diff --git a/py25/bacpypes/iocb.py b/py25/bacpypes/iocb.py
index 3779de8..0674b51 100644
--- a/py25/bacpypes/iocb.py
+++ b/py25/bacpypes/iocb.py
@@ -159,7 +159,7 @@ class IOCB(DebugContents):
         # if there's a timer, cancel it
         if self.ioTimeout:
             if _debug: IOCB._debug("    - cancel timeout")
-            self.ioTimeout.SuspendTask()
+            self.ioTimeout.suspend_task()
 
         # set the completion event
         self.ioComplete.set()
diff --git a/py27/bacpypes/iocb.py b/py27/bacpypes/iocb.py
index 32867d7..5b9119c 100644
--- a/py27/bacpypes/iocb.py
+++ b/py27/bacpypes/iocb.py
@@ -160,7 +160,7 @@ class IOCB(DebugContents):
         # if there's a timer, cancel it
         if self.ioTimeout:
             if _debug: IOCB._debug("    - cancel timeout")
-            self.ioTimeout.SuspendTask()
+            self.ioTimeout.suspend_task()
 
         # set the completion event
         self.ioComplete.set()
diff --git a/py34/bacpypes/iocb.py b/py34/bacpypes/iocb.py
index fce079d..028556a 100644
--- a/py34/bacpypes/iocb.py
+++ b/py34/bacpypes/iocb.py
@@ -160,7 +160,7 @@ class IOCB(DebugContents):
         # if there's a timer, cancel it
         if self.ioTimeout:
             if _debug: IOCB._debug("    - cancel timeout")
-            self.ioTimeout.SuspendTask()
+            self.ioTimeout.suspend_task()
 
         # set the completion event
         self.ioComplete.set()