diff --git a/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.c b/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.c
index b8788d2a58..3b383d89a4 100644
--- a/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.c
+++ b/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.c
@@ -371,8 +371,12 @@ static unsigned zt_open_range(zap_span_t *span, unsigned start, unsigned end, za
 			}
 
 			if (zchan->type == ZAP_CHAN_TYPE_DQ921) {
-				if ((ztp.sig_type != ZT_SIG_HDLCRAW) && (ztp.sig_type != ZT_SIG_HDLCFCS)) {
-					zap_log(ZAP_LOG_ERROR, "failure configuring device %s as OpenZAP device %d:%d fd:%d\n", chanpath, zchan->span_id, zchan->chan_id, sockfd);
+				if (
+					(ztp.sig_type != ZT_SIG_HDLCRAW) &&
+					(ztp.sig_type != ZT_SIG_HDLCFCS) &&
+					(ztp.sig_type != ZT_SIG_HARDHDLC)
+					) {
+					zap_log(ZAP_LOG_ERROR, "Failure configuring device %s as OpenZAP device %d:%d fd:%d, hardware signaling is not HDLC, fix your Zap/DAHDI configuration!\n", chanpath, zchan->span_id, zchan->chan_id, sockfd);
 					close(sockfd);
 					continue;
 				}
diff --git a/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.h b/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.h
index 14516f6fe9..f82cf0ff10 100644
--- a/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.h
+++ b/libs/openzap/src/ozmod/ozmod_zt/ozmod_zt.h
@@ -241,7 +241,8 @@ ZT_SIG_EM					= (1 << 6),					/* E&M */
 ZT_SIG_CLEAR				= (1 << 7),
 ZT_SIG_HDLCRAW				= ((1 << 8)  | ZT_SIG_CLEAR),
 ZT_SIG_HDLCFCS				= ((1 << 9)  | ZT_SIG_HDLCRAW),
-ZT_SIG_CAS                              = (1 << 15)
+ZT_SIG_CAS                  = (1 << 15),
+ZT_SIG_HARDHDLC				= (1 << 19),
 } zt_sigtype_t;
 
 typedef enum {