diff --git a/artiq/gateware/rtio/input_collector.py b/artiq/gateware/rtio/input_collector.py
index b0962adb5..d0cba4f50 100644
--- a/artiq/gateware/rtio/input_collector.py
+++ b/artiq/gateware/rtio/input_collector.py
@@ -4,6 +4,7 @@ from migen.genlib.fifo import *
 
 from artiq.gateware.rtio import cri
 from artiq.gateware.rtio import rtlink
+from artiq.gateware.rtio.cdc import *
 
 
 __all__ = ["InputCollector"]