diff --git a/libs/freetdm/src/isdn/Q931.c b/libs/freetdm/src/isdn/Q931.c
index e1606b0809..232b2122c3 100644
--- a/libs/freetdm/src/isdn/Q931.c
+++ b/libs/freetdm/src/isdn/Q931.c
@@ -335,10 +335,6 @@ L3INT Q931Rx23(Q931_TrunkInfo_t *pTrunk, L3UCHAR * buf, L3INT Size)
     /* Message Type */
     m->MesType = Mes[IOff++];
 
-	if (m->ProtDisc != 8) {
-		return Q931E_UNKNOWN_MESSAGE;
-	}
-
     /* Call table proc to unpack codec message */
 	RetCode = Q931Umes[pTrunk->Dialect][m->MesType](pTrunk, Mes, (Q931mes_Generic *)pTrunk->L3Buf, Q931L4HeaderSpace + IOff , Size - Q931L4HeaderSpace - IOff + 1);