diff --git a/sysmoOCTSIM/usb_descriptors.c b/sysmoOCTSIM/usb_descriptors.c
index ddb925b..944e43b 100644
--- a/sysmoOCTSIM/usb_descriptors.c
+++ b/sysmoOCTSIM/usb_descriptors.c
@@ -113,7 +113,7 @@
 				.bDescriptorType = CDC_CS_INTERFACE,
 				.bDescriptorSubtype = CDC_SCS_UNION,
 				.bMasterInterface = CONF_USB_CDCD_ACM_COMM_BIFCNUM,
-				.bSlaveInterface0 = 0x01,
+				.bSlaveInterface0 = CONF_USB_CDCD_ACM_DATA_BIFCNUM,
 			},
 			.ep = {
 				{