Index: channels/chan_dahdi.c
===================================================================
--- channels/chan_dahdi.c	(revision 401703)
+++ channels/chan_dahdi.c	(working copy)
@@ -13295,8 +13295,27 @@
 	ast_mutex_unlock(&iflock);
 	restart_monitor();
 	if (cause && !tmp) {
+		/*
+		 * If this is a trunk (e.g. FXO with FXSKS signalling) return
+		 * CONGESTION instead of BUSY so that dialplan logic knows to continue
+		 * trying next trunk.
+		 */
 		if (callwait || channelmatched) {
-			*cause = AST_CAUSE_BUSY;
+			/* Look for matching channel again */
+			if (start.channelmatch && p->channel != start.channelmatch) {
+				ast_mutex_lock(&iflock);
+				for (p = iflist; p; p = p->next) {
+					if (p->channel == start.channelmatch) {
+						break;
+					}
+				}
+				ast_mutex_unlock(&iflock);
+			}
+			if (p && ISTRUNK(p)) {
+				*cause = AST_CAUSE_CONGESTION;
+			} else {
+				*cause = AST_CAUSE_BUSY;
+			}
 		} else if (groupmatched) {
 			*cause = AST_CAUSE_CONGESTION;
 		} else {