--- chan_dahdi.c-rel.invalid	2008-09-04 14:31:54.000000000 +0200
+++ chan_dahdi.c	2008-09-04 14:19:46.000000000 +0200
@@ -9522,9 +9522,17 @@
 				ast_mutex_lock(&p->lock);
 				if (p->owner) {
 					if (p->ss7call == e->iam.call) {
-						ast_mutex_unlock(&p->lock);
-						ast_log(LOG_WARNING, "Duplicate IAM requested on CIC %d\n", e->iam.cic);
-						break;
+						ast_log(LOG_WARNING, "Daul seizure on CIC %d!\n", e->iam.cic);
+						if ((e->iam.opc > ss7_get_pc(ss7)) ? (e->iam.cic & 1) : (~e->iam.cic & 1)) {
+							ast_log(LOG_NOTICE, "We are the controlling on CIC: %d, the remote party will step back, ignoring IAM\n", e->iam.cic);
+							ast_mutex_unlock(&p->lock);
+							break;
+						} else {
+							ast_log(LOG_NOTICE, "The remote party is the controlling on CIC: %d, we must step back!\n", e->iam.cic);
+							p->ss7call = NULL;
+							dahdi_hangup(p->owner);
+							p->owner = NULL;
+						}
 					} else {
 						ast_mutex_unlock(&p->lock);
 						ast_log(LOG_WARNING, "Ring requested on CIC %d already in use!\n", e->iam.cic);