diff --git a/src/libosmo-mgcp/mgcp_codec.c b/src/libosmo-mgcp/mgcp_codec.c
index 2ce90dd..55be554 100644
--- a/src/libosmo-mgcp/mgcp_codec.c
+++ b/src/libosmo-mgcp/mgcp_codec.c
@@ -341,3 +341,70 @@
 
 	return -EINVAL;
 }
+
+/* Compare two codecs, all parameters must match up, except for the payload type
+ * number. */
+static bool codecs_cmp(struct mgcp_rtp_codec *codec_a, struct mgcp_rtp_codec *codec_b)
+{
+	if (codec_a->rate != codec_b->rate)
+		return false;
+	if (codec_a->channels != codec_b->channels)
+		return false;
+	if (codec_a->frame_duration_num != codec_b->frame_duration_num)
+		return false;
+	if (codec_a->frame_duration_den != codec_b->frame_duration_den)
+		return false;
+	if (strcmp(codec_a->audio_name, codec_b->audio_name))
+		return false;
+	if (strcmp(codec_a->subtype_name, codec_b->subtype_name))
+		return false;
+
+	return true;
+}
+
+/*! Translate a given payload type number that belongs to the packet of a
+ *  source connection to the equivalent payload type number that matches the
+ *  configuration of a destination connection.
+ *  \param[in] conn_src related source rtp-connection.
+ *  \param[in] conn_dst related destination rtp-connection.
+ *  \param[in] payload_type number from the source packet or source connection.
+ *  \returns translated payload type number on success, -EINVAL on failure. */
+int mgcp_codec_pt_translate(struct mgcp_conn_rtp *conn_src, struct mgcp_conn_rtp *conn_dst, int payload_type)
+{
+	struct mgcp_rtp_end *rtp_src;
+	struct mgcp_rtp_end *rtp_dst;
+	struct mgcp_rtp_codec *codec_src = NULL;
+	struct mgcp_rtp_codec *codec_dst = NULL;
+	unsigned int i;
+	unsigned int codecs_assigned;
+
+	rtp_src = &conn_src->end;
+	rtp_dst = &conn_dst->end;
+
+	/* Find the codec information that is used on the source side */
+	codecs_assigned = rtp_src->codecs_assigned;
+	OSMO_ASSERT(codecs_assigned <= MGCP_MAX_CODECS);
+	for (i = 0; i < codecs_assigned; i++) {
+		if (payload_type == rtp_src->codecs[i].payload_type) {
+			codec_src = &rtp_src->codecs[i];
+			break;
+		}
+	}
+	if (!codec_src)
+		return -EINVAL;
+
+	/* Use the codec infrmation from the source and try to find the
+	 * equivalent of it on the destination side */
+	codecs_assigned = rtp_dst->codecs_assigned;
+	OSMO_ASSERT(codecs_assigned <= MGCP_MAX_CODECS);
+	for (i = 0; i < codecs_assigned; i++) {
+		if (codecs_cmp(codec_src, &rtp_dst->codecs[i])) {
+			codec_dst = &rtp_dst->codecs[i];
+			break;
+		}
+	}
+	if (!codec_dst)
+		return -EINVAL;
+
+	return codec_dst->payload_type;
+}
diff --git a/src/libosmo-mgcp/mgcp_network.c b/src/libosmo-mgcp/mgcp_network.c
index 3ac93be..1b1867a 100644
--- a/src/libosmo-mgcp/mgcp_network.c
+++ b/src/libosmo-mgcp/mgcp_network.c
@@ -40,8 +40,10 @@
 #include <osmocom/mgcp/osmux.h>
 #include <osmocom/mgcp/mgcp_conn.h>
 #include <osmocom/mgcp/mgcp_endp.h>
+#include <osmocom/mgcp/mgcp_codec.h>
 #include <osmocom/mgcp/debug.h>
 
+
 #define RTP_SEQ_MOD		(1 << 16)
 #define RTP_MAX_DROPOUT		3000
 #define RTP_MAX_MISORDER	100
@@ -474,6 +476,28 @@
 	state->stats.max_seq = seq;
 }
 
+/* There may be different payload type numbers negotiated for two connections.
+ * Patch the payload type of an RTP packet so that it uses the payload type
+ * that is valid for the destination connection (conn_dst) */
+static int mgcp_patch_pt(struct mgcp_conn_rtp *conn_src,
+			 struct mgcp_conn_rtp *conn_dst, char *data, int len)
+{
+	struct rtp_hdr *rtp_hdr;
+	uint8_t pt_in;
+	int pt_out;
+
+	OSMO_ASSERT(len >= sizeof(struct rtp_hdr));
+	rtp_hdr = (struct rtp_hdr *)data;
+
+	pt_in = rtp_hdr->payload_type;
+	pt_out = mgcp_codec_pt_translate(conn_src, conn_dst, pt_in);
+	if (pt_out < 0)
+		return -EINVAL;
+
+	rtp_hdr->payload_type = (uint8_t) pt_out;
+	return 0;
+}
+
 /* The RFC 3550 Appendix A assumes there are multiple sources but
  * some of the supported endpoints (e.g. the nanoBTS) can only handle
  * one source and this code will patch RTP header to appear as if there
@@ -665,6 +689,7 @@
 	struct mgcp_rtp_end *rtp_end;
 	struct mgcp_rtp_state *rtp_state;
 	char *dest_name;
+	int rc;
 
 	OSMO_ASSERT(conn_src);
 	OSMO_ASSERT(conn_dst);
@@ -684,6 +709,21 @@
 	     ENDPOINT_NUMBER(endp), tcfg->audio_loop, conn_src->conn->mode,
 	     conn_src->conn->mode == MGCP_CONN_LOOPBACK ? " (loopback)" : "");
 
+	/* FIXME: It is legal that the payload type on the egress connection is
+	 * different from the payload type that has been negotiated on the
+	 * ingress connection. Essentially the codecs are the same so we can
+	 * match them and patch the payload type. However, if we can not find
+	 * the codec pendant (everything ist equal except the PT), we are of
+	 * course unable to patch the payload type. A situation like this
+	 * should not occur if transcoding is consequently avoided. Until
+	 * we have transcoding support in osmo-mgw we can not resolve this. */
+	rc = mgcp_patch_pt(conn_src, conn_dst, buf, len);
+	if (rc < 0) {
+		LOGP(DRTP, LOGL_ERROR,
+		     "endpoint:0x%x can not patch PT because no suitable egress codec was found.\n",
+		     ENDPOINT_NUMBER(endp));
+	}
+
 	/* Note: In case of loopback configuration, both, the source and the
 	 * destination will point to the same connection. */
 	rtp_end = &conn_dst->end;