diff --git a/src/mess/drivers/pet.c b/src/mess/drivers/pet.c
index d6ccabca4ef..f6feb2c1b67 100644
--- a/src/mess/drivers/pet.c
+++ b/src/mess/drivers/pet.c
@@ -879,8 +879,8 @@ const via6522_interface via_intf =
 	DEVCB_DRIVER_MEMBER(pet_state, via_pa_w),
 	DEVCB_DRIVER_MEMBER(pet_state, via_pb_w),
 	DEVCB_DEVICE_LINE_MEMBER(PET_USER_PORT_TAG, pet_user_port_device, ca1_w),
-	DEVCB_DRIVER_LINE_MEMBER(pet_state, via_ca2_w),
 	DEVCB_NULL,
+	DEVCB_DRIVER_LINE_MEMBER(pet_state, via_ca2_w),
 	DEVCB_DRIVER_LINE_MEMBER(pet_state, via_cb2_w),
 	DEVCB_DRIVER_LINE_MEMBER(pet_state, via_irq_w)
 };