diff --git a/src/modules/module-udev-detect.c b/src/modules/module-udev-detect.c
index a12f7c936..f17695b31 100644
--- a/src/modules/module-udev-detect.c
+++ b/src/modules/module-udev-detect.c
@@ -366,7 +366,7 @@ static void process_device(struct userdata *u, struct udev_device *dev) {
         return;
     }
 
-    if ((ff = udev_device_get_property_value(dev, "SOUND_FORM_FACTOR")) &&
+    if ((ff = udev_device_get_property_value(dev, "SOUND_CLASS")) &&
         pa_streq(ff, "modem")) {
         pa_log_debug("Ignoring %s, because it is a modem.", udev_device_get_devpath(dev));
         return;