diff --git a/libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_cfg.c b/libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_cfg.c
index 1bd2753e81..be6ba07884 100644
--- a/libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_cfg.c
+++ b/libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_cfg.c
@@ -745,8 +745,16 @@ ftdm_status_t sngisdn_stack_cfg_q931_dlsap(ftdm_span_t *span)
 	/* TODO: Fill in these timers with proper values - eventually pass them */
 	cfg.t.cfg.s.inDLSAP.tmr.t301.enb = TRUE;
 	cfg.t.cfg.s.inDLSAP.tmr.t301.val = 180;
-	cfg.t.cfg.s.inDLSAP.tmr.t302.enb = TRUE;
-	cfg.t.cfg.s.inDLSAP.tmr.t302.val = 15;
+
+	/* It looks like ETSI is the only variant that supports Overlap */s
+	if (signal_data->switchtype == SNGISDN_SWITCH_EUROISDN) {
+		cfg.t.cfg.s.inDLSAP.tmr.t302.enb = TRUE;
+		cfg.t.cfg.s.inDLSAP.tmr.t302.val = 15;
+	} else {
+		cfg.t.cfg.s.inDLSAP.tmr.t302.enb = FALSE;
+		cfg.t.cfg.s.inDLSAP.tmr.t302.val = 0;
+	}
+
 	cfg.t.cfg.s.inDLSAP.tmr.t303.enb = TRUE;
 	cfg.t.cfg.s.inDLSAP.tmr.t303.val = 4;
 	cfg.t.cfg.s.inDLSAP.tmr.t304.enb = TRUE;