diff --git a/include/osmocom/msc/Makefile.am b/include/osmocom/msc/Makefile.am
index 948021a..3286c37 100644
--- a/include/osmocom/msc/Makefile.am
+++ b/include/osmocom/msc/Makefile.am
@@ -3,6 +3,8 @@
 	cell_id_list.h \
 	codec_filter.h \
 	codec_mapping.h \
+	csd_bs.h \
+	csd_filter.h \
 	db.h \
 	debug.h \
 	e_link.h \
diff --git a/include/osmocom/msc/csd_bs.h b/include/osmocom/msc/csd_bs.h
new file mode 100644
index 0000000..eee8692
--- /dev/null
+++ b/include/osmocom/msc/csd_bs.h
@@ -0,0 +1,54 @@
+/* 3GPP TS 122.002 Bearer Services */
+#pragma once
+
+#include <osmocom/gsm/mncc.h>
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+
+enum csd_bs {
+	CSD_BS_NONE,
+
+	/* 3.1.1.1.2 */
+	CSD_BS_21_T_V110_0k3,
+	CSD_BS_22_T_V110_1k2,
+	CSD_BS_24_T_V110_2k4,
+	CSD_BS_25_T_V110_4k8,
+	CSD_BS_26_T_V110_9k6,
+
+	/* 3.1.1.2.2 */
+	CSD_BS_21_NT_V110_0k3,
+	CSD_BS_22_NT_V110_1k2,
+	CSD_BS_24_NT_V110_2k4,
+	CSD_BS_25_NT_V110_4k8,
+	CSD_BS_26_NT_V110_9k6,
+
+	/* 3.1.2.1.2 */
+	CSD_BS_31_T_V110_1k2,
+	CSD_BS_32_T_V110_2k4,
+	CSD_BS_33_T_V110_4k8,
+	CSD_BS_34_T_V110_9k6,
+
+	CSD_BS_MAX,
+};
+
+struct csd_bs_list {
+	unsigned int count;
+	enum csd_bs bs[CSD_BS_MAX];
+};
+
+void csd_bs_list_add_bs(struct csd_bs_list *list, enum csd_bs bs);
+int csd_bs_list_to_bearer_cap(struct gsm_mncc_bearer_cap *cap, const struct csd_bs_list *list);
+void csd_bs_list_from_bearer_cap(struct csd_bs_list *list, const struct gsm_mncc_bearer_cap *cap);
+
+int csd_bs_to_str_buf(char *buf, size_t buflen, enum csd_bs bs);
+char *csd_bs_to_str_c(void *ctx, enum csd_bs bs);
+const char *csd_bs_to_str(enum csd_bs bs);
+
+int csd_bs_list_to_str_buf(char *buf, size_t buflen, const struct csd_bs_list *list);
+char *csd_bs_list_to_str_c(void *ctx, const struct csd_bs_list *list);
+const char *csd_bs_list_to_str(const struct csd_bs_list *list);
+
+void csd_bs_list_add_bs(struct csd_bs_list *list, enum csd_bs bs);
+void csd_bs_list_remove(struct csd_bs_list *list, enum csd_bs bs);
+void csd_bs_list_intersection(struct csd_bs_list *dest, const struct csd_bs_list *other);
+
+int csd_bs_list_to_gsm0808_channel_type(struct gsm0808_channel_type *ct, const struct csd_bs_list *list);
diff --git a/include/osmocom/msc/csd_filter.h b/include/osmocom/msc/csd_filter.h
new file mode 100644
index 0000000..51ffff7
--- /dev/null
+++ b/include/osmocom/msc/csd_filter.h
@@ -0,0 +1,53 @@
+/* Filter/overlay data rates for CSD, across MS, RAN and CN limitations */
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Oliver Smith
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#pragma once
+
+#include <osmocom/gsm/gsm_utils.h>
+#include <osmocom/gsm/mncc.h>
+#include <osmocom/mgcp_client/mgcp_client.h>
+
+#include <osmocom/msc/csd_bs.h>
+#include <osmocom/msc/sdp_msg.h>
+
+/* Combine various data rate selections to obtain a resulting set allowed by
+ * all of them. Members reflect the different entities/stages that select data
+ * rates in CSD. Call csd_filter_run() and obtain the resulting set in
+ * csd_filter.result. */
+struct csd_filter {
+	/* The fixed set available on the RAN type, per definition. */
+	struct csd_bs_list ran;
+	/* The services advertised by the MS Bearer Capabilities */
+	struct csd_bs_list ms;
+	/* If known, the set the current RAN cell allows / has available. This
+	 * may not be available if the BSC does not issue this information
+	 * early enough. Should be ignored if empty. */
+	struct csd_bs_list bss;
+
+	/* After a channel was assigned, this reflects the chosen BS. */
+	enum csd_bs assignment;
+};
+
+void csd_filter_set_ran(struct csd_filter *filter, enum osmo_rat_type ran_type);
+int csd_filter_run(struct csd_filter *filter, struct sdp_msg *result, const struct sdp_msg *remote);
+
+int csd_filter_to_str_buf(char *buf, size_t buflen, const struct csd_filter *filter,
+			    const struct sdp_msg *result, const struct sdp_msg *remote);
+char *csd_filter_to_str_c(void *ctx, const struct csd_filter *filter, const struct sdp_msg *result, const struct sdp_msg *remote);
+const char *csd_filter_to_str(const struct csd_filter *filter, const struct sdp_msg *result, const struct sdp_msg *remote);
diff --git a/include/osmocom/msc/sdp_msg.h b/include/osmocom/msc/sdp_msg.h
index 1b905b7..e62f22b 100644
--- a/include/osmocom/msc/sdp_msg.h
+++ b/include/osmocom/msc/sdp_msg.h
@@ -4,6 +4,8 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/core/sockaddr_str.h>
 
+#include <osmocom/msc/csd_bs.h>
+
 extern const struct value_string sdp_msg_payload_type_names[];
 static inline const char *sdp_msg_payload_type_name(unsigned int payload_type)
 { return get_value_string(sdp_msg_payload_type_names, payload_type); }
@@ -36,6 +38,7 @@
 	unsigned int ptime;
 	enum sdp_mode_e mode;
 	struct sdp_audio_codecs audio_codecs;
+	struct csd_bs_list bearer_services;
 };
 
 #define foreach_sdp_audio_codec(/* struct sdp_audio_codec* */ CODEC, \
@@ -80,3 +83,5 @@
 int sdp_msg_to_str_buf(char *buf, size_t buflen, const struct sdp_msg *sdp);
 char *sdp_msg_to_str_c(void *ctx, const struct sdp_msg *sdp);
 const char *sdp_msg_to_str(const struct sdp_msg *sdp);
+
+void sdp_audio_codecs_set_csd(struct sdp_audio_codecs *ac);
diff --git a/include/osmocom/msc/transaction.h b/include/osmocom/msc/transaction.h
index 36aab78..d2a463d 100644
--- a/include/osmocom/msc/transaction.h
+++ b/include/osmocom/msc/transaction.h
@@ -9,6 +9,7 @@
 #include <osmocom/msc/msc_a.h>
 #include <osmocom/msc/debug.h>
 #include <osmocom/msc/codec_filter.h>
+#include <osmocom/msc/csd_filter.h>
 #include <osmocom/gsm/gsm0411_smc.h>
 #include <osmocom/gsm/gsm0411_smr.h>
 
@@ -107,8 +108,9 @@
 			struct osmo_lcls *lcls;
 			/* SDP as last received from the remote call leg. */
 			struct sdp_msg remote;
-			/* Track codec choices from BSS and remote call leg */
+			/* Track codec/CSD choices from BSS and remote call leg */
 			struct codec_filter codecs;
+			struct csd_filter csd;
 			/* Resulting choice from codecs/bearer services and the
 			 * local RTP address to be sent to the remote call leg. */
 			struct sdp_msg local;
diff --git a/src/libmsc/Makefile.am b/src/libmsc/Makefile.am
index 9577475..fba7b53 100644
--- a/src/libmsc/Makefile.am
+++ b/src/libmsc/Makefile.am
@@ -29,6 +29,8 @@
 	cell_id_list.c \
 	codec_filter.c \
 	codec_mapping.c \
+	csd_bs.c \
+	csd_filter.c \
 	sccp_ran.c \
 	msc_vty.c \
 	db.c \
diff --git a/src/libmsc/csd_bs.c b/src/libmsc/csd_bs.c
new file mode 100644
index 0000000..adb9293
--- /dev/null
+++ b/src/libmsc/csd_bs.c
@@ -0,0 +1,477 @@
+/* 3GPP TS 122.002 Bearer Services */
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Oliver Smith
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <errno.h>
+
+#include <osmocom/msc/csd_bs.h>
+#include <osmocom/msc/debug.h>
+
+/* csd_bs related below */
+
+struct csd_bs_map {
+	/* BS number (20, 21, ...) */
+	unsigned int num;
+	/* Access Structure (1: asynchronous, 0: synchronous) */
+	bool async;
+	/* QoS Attribute (1: transparent, 0: non-transparent) */
+	bool transp;
+	/* Rate Adaption (V110, V120 etc.) */
+	enum gsm48_bcap_ra ra;
+	/* Fixed Network User Rate */
+	unsigned int rate;
+};
+
+static const struct csd_bs_map bs_map[] = {
+	/* 3.1.1.1.2 */
+	[CSD_BS_21_T_V110_0k3] = {
+		.num = 21,
+		.async = true,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 300,
+	},
+	[CSD_BS_22_T_V110_1k2] = {
+		.num = 22,
+		.async = true,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 1200,
+	},
+	[CSD_BS_24_T_V110_2k4] = {
+		.num = 24,
+		.async = true,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 2400,
+	},
+	[CSD_BS_25_T_V110_4k8] = {
+		.num = 25,
+		.async = true,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 4800,
+	},
+	[CSD_BS_26_T_V110_9k6] = {
+		.num = 26,
+		.async = true,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 9600,
+	},
+
+	/* 3.1.1.2.2 */
+	[CSD_BS_21_NT_V110_0k3] = {
+		.num = 21,
+		.async = true,
+		.transp = false,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 300,
+	},
+	[CSD_BS_22_NT_V110_1k2] = {
+		.num = 22,
+		.async = true,
+		.transp = false,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 1200,
+	},
+	[CSD_BS_24_NT_V110_2k4] = {
+		.num = 24,
+		.async = true,
+		.transp = false,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 2400,
+	},
+	[CSD_BS_25_NT_V110_4k8] = {
+		.num = 25,
+		.async = true,
+		.transp = false,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 4800,
+	},
+	[CSD_BS_26_NT_V110_9k6] = {
+		.num = 26,
+		.async = true,
+		.transp = false,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 9600,
+	},
+
+	/* 3.1.2.1.2 */
+	[CSD_BS_31_T_V110_1k2] = {
+		.num = 31,
+		.async = false,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 1200,
+	},
+	[CSD_BS_32_T_V110_2k4] = {
+		.num = 32,
+		.async = false,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 2400,
+	},
+	[CSD_BS_33_T_V110_4k8] = {
+		.num = 33,
+		.async = false,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 4800,
+	},
+	[CSD_BS_34_T_V110_9k6] = {
+		.num = 34,
+		.async = false,
+		.transp = true,
+		.ra = GSM48_BCAP_RA_V110_X30,
+		.rate = 9600,
+	},
+};
+
+osmo_static_assert(ARRAY_SIZE(bs_map) == CSD_BS_MAX, _invalid_size_bs_map);
+
+bool csd_bs_is_transp(enum csd_bs bs)
+{
+	return bs_map[bs].transp;
+}
+
+/* Short single-line representation, convenient for logging.
+ * Like "BS25NT" */
+int csd_bs_to_str_buf(char *buf, size_t buflen, enum csd_bs bs)
+{
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	const struct csd_bs_map *map = &bs_map[bs];
+
+	OSMO_STRBUF_PRINTF(sb, "BS%u%s",
+			   map->num,
+			   map->transp ? "T" : "NT");
+
+	if (map->ra != GSM48_BCAP_RA_V110_X30)
+		OSMO_STRBUF_PRINTF(sb, "-RA=%d", map->ra);
+
+	return sb.chars_needed;
+}
+
+char *csd_bs_to_str_c(void *ctx, enum csd_bs bs)
+{
+	OSMO_NAME_C_IMPL(ctx, 32, "csd_bs_to_str_c-ERROR", csd_bs_to_str_buf, bs)
+}
+
+const char *csd_bs_to_str(enum csd_bs bs)
+{
+	return csd_bs_to_str_c(OTC_SELECT, bs);
+}
+
+static int csd_bs_to_gsm0808_data_rate_transp(enum csd_bs bs)
+{
+	switch (bs_map[bs].rate) {
+	case 1200:
+		return GSM0808_DATA_RATE_TRANSP_1k2;
+	case 2400:
+		return GSM0808_DATA_RATE_TRANSP_2k4;
+	case 4800:
+		return GSM0808_DATA_RATE_TRANSP_4k8;
+	case 9600:
+		return GSM0808_DATA_RATE_TRANSP_9k6;
+	}
+	return -EINVAL;
+}
+
+static int csd_bs_to_gsm0808_data_rate_non_transp(enum csd_bs bs)
+{
+	uint16_t rate = bs_map[bs].rate;
+
+	if (rate < 6000)
+		return GSM0808_DATA_RATE_NON_TRANSP_6k0;
+	if (rate < 12000)
+		return GSM0808_DATA_RATE_NON_TRANSP_12k0;
+
+	return -EINVAL;
+}
+
+static int csd_bs_to_gsm0808_data_rate_non_transp_allowed(enum csd_bs bs)
+{
+	uint16_t rate = bs_map[bs].rate;
+
+	if (rate < 6000)
+		return GSM0808_DATA_RATE_NON_TRANSP_ALLOWED_6k0;
+	if (rate < 12000)
+		return GSM0808_DATA_RATE_NON_TRANSP_ALLOWED_12k0;
+
+	return -EINVAL;
+}
+
+enum csd_bs csd_bs_from_bearer_cap(const struct gsm_mncc_bearer_cap *cap, bool transp)
+{
+	enum gsm48_bcap_ra ra = cap->data.rate_adaption;
+	enum gsm48_bcap_user_rate rate = cap->data.user_rate;
+	bool async = cap->data.async;
+
+	if (ra == GSM48_BCAP_RA_V110_X30 && async && transp) {
+		switch (rate) {
+		case GSM48_BCAP_UR_300:
+			return CSD_BS_21_T_V110_0k3;
+		case GSM48_BCAP_UR_1200:
+			return CSD_BS_22_T_V110_1k2;
+		case GSM48_BCAP_UR_2400:
+			return CSD_BS_24_T_V110_2k4;
+		case GSM48_BCAP_UR_4800:
+			return CSD_BS_25_T_V110_4k8;
+		case GSM48_BCAP_UR_9600:
+			return CSD_BS_26_T_V110_9k6;
+		default:
+			return CSD_BS_NONE;
+		}
+	}
+
+	if (ra == GSM48_BCAP_RA_V110_X30 && async && !transp) {
+		switch (rate) {
+		case GSM48_BCAP_UR_300:
+			return CSD_BS_21_NT_V110_0k3;
+		case GSM48_BCAP_UR_1200:
+			return CSD_BS_22_NT_V110_1k2;
+		case GSM48_BCAP_UR_2400:
+			return CSD_BS_24_NT_V110_2k4;
+		case GSM48_BCAP_UR_4800:
+			return CSD_BS_25_NT_V110_4k8;
+		case GSM48_BCAP_UR_9600:
+			return CSD_BS_26_NT_V110_9k6;
+		default:
+			return CSD_BS_NONE;
+		}
+	}
+
+	if (ra == GSM48_BCAP_RA_V110_X30 && !async && transp) {
+		switch (rate) {
+		case GSM48_BCAP_UR_1200:
+			return CSD_BS_31_T_V110_1k2;
+		case GSM48_BCAP_UR_2400:
+			return CSD_BS_32_T_V110_2k4;
+		case GSM48_BCAP_UR_4800:
+			return CSD_BS_33_T_V110_4k8;
+		case GSM48_BCAP_UR_9600:
+			return CSD_BS_34_T_V110_9k6;
+		default:
+			return CSD_BS_NONE;
+		}
+	}
+
+	return CSD_BS_NONE;
+}
+
+/* csd_bs_list related below */
+
+int csd_bs_list_to_str_buf(char *buf, size_t buflen, const struct csd_bs_list *list)
+{
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	int i;
+
+	if (!list->count)
+		OSMO_STRBUF_PRINTF(sb, "(no-bearer-services)");
+
+	for (i = 0; i < list->count; i++) {
+		if (i)
+			OSMO_STRBUF_PRINTF(sb, ",");
+
+		OSMO_STRBUF_APPEND(sb, csd_bs_to_str_buf, list->bs[i]);
+	}
+	return sb.chars_needed;
+}
+
+char *csd_bs_list_to_str_c(void *ctx, const struct csd_bs_list *list)
+{
+	OSMO_NAME_C_IMPL(ctx, 128, "csd_bs_list_to_str_c-ERROR", csd_bs_list_to_str_buf, list)
+}
+
+const char *csd_bs_list_to_str(const struct csd_bs_list *list)
+{
+	return csd_bs_list_to_str_c(OTC_SELECT, list);
+}
+
+bool csd_bs_list_has_bs(const struct csd_bs_list *list, enum csd_bs bs)
+{
+	int i;
+
+	for (i = 0; i < list->count; i++) {
+		if (list->bs[i] == bs)
+			return true;
+	}
+
+	return false;
+}
+
+void csd_bs_list_add_bs(struct csd_bs_list *list, enum csd_bs bs)
+{
+	int i;
+
+	if (!bs)
+		return;
+
+	for (i = 0; i < list->count; i++) {
+		if (list->bs[i] == bs)
+			return;
+	}
+
+	list->bs[i] = bs;
+	list->count++;
+}
+
+void csd_bs_list_remove(struct csd_bs_list *list, enum csd_bs bs)
+{
+	int i;
+	bool found = false;
+
+	for (i = 0; i < list->count; i++) {
+		if (list->bs[i] == bs) {
+			found = true;
+			list->count--;
+			continue;
+		}
+		if (i && found)
+			list->bs[i-1] = list->bs[i];
+	}
+}
+
+void csd_bs_list_intersection(struct csd_bs_list *dest, const struct csd_bs_list *other)
+{
+	int i;
+
+	for (i = 0; i < dest->count; i++) {
+		if (csd_bs_list_has_bs(other, dest->bs[i]))
+			continue;
+		csd_bs_list_remove(dest, dest->bs[i]);
+		i--;
+	}
+}
+
+int csd_bs_list_to_gsm0808_channel_type(struct gsm0808_channel_type *ct, const struct csd_bs_list *list)
+{
+	int i;
+	int rc;
+
+	*ct = (struct gsm0808_channel_type){
+		.ch_indctr = GSM0808_CHAN_DATA,
+	};
+
+	OSMO_ASSERT(list->count);
+
+	if (csd_bs_is_transp(list->bs[0])) {
+		ct->data_transparent = true;
+		ct->data_rate = csd_bs_to_gsm0808_data_rate_transp(list->bs[0]);
+	} else {
+		ct->data_rate = csd_bs_to_gsm0808_data_rate_non_transp(list->bs[0]);
+	}
+
+	if (ct->data_rate < 0)
+		return -EINVAL;
+
+	/* Other possible data rates allowed (3GPP TS 48.008 § 3.2.2.11, 5a) */
+	if (!ct->data_transparent && list->count > 1) {
+		for (i = 1; i < list->count; i++) {
+			if (!csd_bs_is_transp(list->bs[i]))
+				continue;
+
+			rc = csd_bs_to_gsm0808_data_rate_non_transp_allowed(list->bs[i]);
+			if (rc < 0) {
+				LOGP(DMSC, LOGL_DEBUG, "Failed to convert %s to allowed r i/f rate\n",
+				     csd_bs_to_str(list->bs[i]));
+				continue;
+			}
+
+			ct->data_rate_allowed |= rc;
+		}
+		if (ct->data_rate_allowed)
+			ct->data_rate_allowed_is_set = true;
+	}
+
+	ct->ch_rate_type = GSM0808_SPEECH_FULL_BM;
+
+	return 0;
+}
+
+int csd_bs_list_to_bearer_cap(struct gsm_mncc_bearer_cap *cap, const struct csd_bs_list *list)
+{
+	*cap = (struct gsm_mncc_bearer_cap){
+		.transfer = GSM_MNCC_BCAP_UNR_DIG,
+	};
+	enum csd_bs bs;
+	int i;
+
+	for (i = 0; i < list->count; i++) {
+		bs = list->bs[i];
+
+		cap->data.rate_adaption = GSM48_BCAP_RA_V110_X30;
+		cap->data.async = bs_map[bs].async;
+		cap->data.transp = bs_map[bs].transp;
+
+		switch (bs_map[bs].rate) {
+		case 300:
+			cap->data.user_rate = GSM48_BCAP_UR_300;
+			break;
+		case 1200:
+			cap->data.user_rate = GSM48_BCAP_UR_1200;
+			break;
+		case 2400:
+			cap->data.user_rate = GSM48_BCAP_UR_2400;
+			break;
+		case 4800:
+			cap->data.user_rate = GSM48_BCAP_UR_4800;
+			break;
+		case 9600:
+			cap->data.user_rate = GSM48_BCAP_UR_9600;
+			break;
+		}
+
+		/* FIXME: handle more than one list entry */
+		return 1;
+	}
+
+	return 0;
+}
+
+void csd_bs_list_from_bearer_cap(struct csd_bs_list *list, const struct gsm_mncc_bearer_cap *cap)
+{
+	*list = (struct csd_bs_list){};
+
+	switch (cap->data.transp) {
+	case GSM48_BCAP_TR_TRANSP:
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, true));
+		break;
+	case GSM48_BCAP_TR_RLP: /* NT */
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, false));
+		break;
+	case GSM48_BCAP_TR_TR_PREF:
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, true));
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, false));
+		break;
+	case GSM48_BCAP_TR_RLP_PREF:
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, false));
+		csd_bs_list_add_bs(list, csd_bs_from_bearer_cap(cap, true));
+		break;
+	}
+
+	if (!list->count) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to get bearer service from bearer capabilities ra=%d, async=%d,"
+		     " transp=%d, user_rate=%d\n", cap->data.rate_adaption, cap->data.async, cap->data.transp,
+		     cap->data.user_rate);
+		return;
+	}
+}
diff --git a/src/libmsc/csd_filter.c b/src/libmsc/csd_filter.c
new file mode 100644
index 0000000..0f428cf
--- /dev/null
+++ b/src/libmsc/csd_filter.c
@@ -0,0 +1,157 @@
+/* Filter/overlay bearer service selections across MS, RAN and CN limitations */
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Oliver Smith
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <osmocom/mgcp_client/mgcp_client.h>
+
+#include <osmocom/msc/csd_filter.h>
+
+static void add_all_geran_bs(struct csd_bs_list *list)
+{
+	/* See 3GPP TS 122.002 Bearer Services */
+	/* In order of preference. TODO: make configurable */
+
+	/* GSM-R */
+	csd_bs_list_add_bs(list, CSD_BS_24_T_V110_2k4);
+	csd_bs_list_add_bs(list, CSD_BS_25_T_V110_4k8);
+	csd_bs_list_add_bs(list, CSD_BS_26_T_V110_9k6);
+
+	/* Other */
+	csd_bs_list_add_bs(list, CSD_BS_21_T_V110_0k3);
+	csd_bs_list_add_bs(list, CSD_BS_22_T_V110_1k2);
+	csd_bs_list_add_bs(list, CSD_BS_21_NT_V110_0k3);
+	csd_bs_list_add_bs(list, CSD_BS_22_NT_V110_1k2);
+	csd_bs_list_add_bs(list, CSD_BS_24_NT_V110_2k4);
+	csd_bs_list_add_bs(list, CSD_BS_25_NT_V110_4k8);
+	csd_bs_list_add_bs(list, CSD_BS_26_NT_V110_9k6);
+	csd_bs_list_add_bs(list, CSD_BS_31_T_V110_1k2);
+	csd_bs_list_add_bs(list, CSD_BS_32_T_V110_2k4);
+	csd_bs_list_add_bs(list, CSD_BS_33_T_V110_4k8);
+	csd_bs_list_add_bs(list, CSD_BS_34_T_V110_9k6);
+}
+
+static void add_all_utran_bs(struct csd_bs_list *list)
+{
+	/* See 3GPP TS 122.002 Bearer Services */
+	/* In order of preference. TODO: make configurable */
+	csd_bs_list_add_bs(list, CSD_BS_21_NT_V110_0k3);
+	csd_bs_list_add_bs(list, CSD_BS_22_NT_V110_1k2);
+	csd_bs_list_add_bs(list, CSD_BS_24_NT_V110_2k4);
+	csd_bs_list_add_bs(list, CSD_BS_25_NT_V110_4k8);
+	csd_bs_list_add_bs(list, CSD_BS_26_NT_V110_9k6);
+}
+
+void csd_filter_set_ran(struct csd_filter *filter, enum osmo_rat_type ran_type)
+{
+	filter->ran = (struct csd_bs_list){};
+
+	switch (ran_type) {
+	default:
+	case OSMO_RAT_GERAN_A:
+		add_all_geran_bs(&filter->ran);
+		break;
+	case OSMO_RAT_UTRAN_IU:
+		add_all_utran_bs(&filter->ran);
+		break;
+	}
+}
+
+int csd_filter_run(struct csd_filter *filter, struct sdp_msg *result, const struct sdp_msg *remote)
+{
+	struct csd_bs_list *r = &result->bearer_services;
+	enum csd_bs a = filter->assignment;
+
+	*r = filter->ran;
+
+	if (filter->ms.count)
+		csd_bs_list_intersection(r, &filter->ms);
+	if (filter->bss.count)
+		csd_bs_list_intersection(r, &filter->bss);
+	if (remote->bearer_services.count)
+		csd_bs_list_intersection(r, &remote->bearer_services);
+
+	/* Future: If osmo-msc were able to trigger a re-assignment [...] see
+	 * comment in codec_filter_run(). */
+
+	if (a) {
+		*r = (struct csd_bs_list){};
+		csd_bs_list_add_bs(r, a);
+	}
+
+	result->audio_codecs.count = 1;
+	result->audio_codecs.codec[0] = (struct sdp_audio_codec){
+		.payload_type = CODEC_CLEARMODE,
+		.subtype_name = "CLEARMODE",
+		.rate = 8000,
+	};
+
+	return 0;
+}
+
+
+int csd_filter_to_str_buf(char *buf, size_t buflen, const struct csd_filter *filter,
+			    const struct sdp_msg *result, const struct sdp_msg *remote)
+{
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	OSMO_STRBUF_APPEND(sb, sdp_msg_to_str_buf, result);
+	OSMO_STRBUF_PRINTF(sb, " (from:");
+
+	if (filter->assignment) {
+		OSMO_STRBUF_PRINTF(sb, " assigned=");
+		OSMO_STRBUF_APPEND(sb, csd_bs_to_str_buf, filter->assignment);
+	}
+
+	if (remote->bearer_services.count || osmo_sockaddr_str_is_nonzero(&remote->rtp)) {
+		OSMO_STRBUF_PRINTF(sb, " remote=");
+		OSMO_STRBUF_APPEND(sb, sdp_msg_to_str_buf, remote);
+	}
+
+	if (filter->ms.count) {
+		OSMO_STRBUF_PRINTF(sb, " MS={");
+		OSMO_STRBUF_APPEND(sb, csd_bs_list_to_str_buf, &filter->ms);
+		OSMO_STRBUF_PRINTF(sb, "}");
+	}
+
+	if (filter->bss.count) {
+		OSMO_STRBUF_PRINTF(sb, " bss={");
+		OSMO_STRBUF_APPEND(sb, csd_bs_list_to_str_buf, &filter->bss);
+		OSMO_STRBUF_PRINTF(sb, "}");
+	}
+
+	OSMO_STRBUF_PRINTF(sb, " RAN={");
+	OSMO_STRBUF_APPEND(sb, csd_bs_list_to_str_buf, &filter->ran);
+	OSMO_STRBUF_PRINTF(sb, "}");
+
+	OSMO_STRBUF_PRINTF(sb, ")");
+
+	return sb.chars_needed;
+}
+
+char *csd_filter_to_str_c(void *ctx, const struct csd_filter *filter, const struct sdp_msg *result, const struct sdp_msg *remote)
+{
+	OSMO_NAME_C_IMPL(ctx, 128, "csd_filter_to_str_c-ERROR", csd_filter_to_str_buf, filter, result, remote)
+}
+
+const char *csd_filter_to_str(const struct csd_filter *filter, const struct sdp_msg *result, const struct sdp_msg *remote)
+{
+	return csd_filter_to_str_c(OTC_SELECT, filter, result, remote);
+}
diff --git a/src/libmsc/gsm_04_08_cc.c b/src/libmsc/gsm_04_08_cc.c
index 4bc87af..1d99421 100644
--- a/src/libmsc/gsm_04_08_cc.c
+++ b/src/libmsc/gsm_04_08_cc.c
@@ -808,55 +808,86 @@
 	trans_cc_filter_set_bss(trans, trans->msc_a);
 	if (setup->fields & MNCC_F_BEARER_CAP)
 		trans->bearer_cap.transfer = setup->bearer_cap.transfer;
-	/* sdp.remote: if SDP is included in the MNCC, take that as definitive list of remote audio codecs. */
-	rx_mncc_sdp(trans, setup->msg_type, setup->sdp);
-	/* sdp.remote: if there is no SDP information or we failed to parse it, try using the Bearer Capability from
-	 * MNCC, if any. */
-	if (!trans->cc.remote.audio_codecs.count && (setup->fields & MNCC_F_BEARER_CAP)) {
-		trans->cc.remote = (struct sdp_msg){};
-		trans_cc_set_remote_from_bc(trans, &setup->bearer_cap);
-		LOG_TRANS_CAT(trans, DMNCC, LOGL_DEBUG, "rx %s Bearer Cap: remote=%s\n",
-			      get_mncc_name(setup->msg_type), sdp_msg_to_str(&trans->cc.remote));
+
+	switch (trans->bearer_cap.transfer) {
+	case GSM48_BCAP_ITCAP_SPEECH:
+		/* sdp.remote: if SDP is included in the MNCC, take that as definitive list of remote audio codecs. */
+		rx_mncc_sdp(trans, setup->msg_type, setup->sdp);
+		/* sdp.remote: if there is no SDP information or we failed to parse it, try using the Bearer Capability from
+		 * MNCC, if any. */
+		if (!trans->cc.remote.audio_codecs.count && (setup->fields & MNCC_F_BEARER_CAP)) {
+			trans->cc.remote = (struct sdp_msg){};
+			trans_cc_set_remote_from_bc(trans, &setup->bearer_cap);
+			LOG_TRANS_CAT(trans, DMNCC, LOGL_DEBUG, "rx %s Bearer Cap: remote=%s\n",
+				      get_mncc_name(setup->msg_type), sdp_msg_to_str(&trans->cc.remote));
+		}
+		if (!trans->cc.remote.audio_codecs.count)
+			LOG_TRANS(trans, LOGL_INFO,
+				  "Got no information of remote audio codecs: neither SDP nor Bearer Capability. Trying anyway.\n");
+		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		sdp_audio_codecs_set_csd(&trans->cc.codecs.ms);
+		break;
+	default:
+		LOG_TRANS(trans, LOGL_ERROR, "Handling of information transfer capability %d not implemented\n",
+			  trans->bearer_cap.transfer);
 	}
-	if (!trans->cc.remote.audio_codecs.count)
-		LOG_TRANS(trans, LOGL_INFO,
-			  "Got no information of remote audio codecs: neither SDP nor Bearer Capability. Trying anyway.\n");
 
 	trans_cc_filter_run(trans);
 
-	/* Compose Bearer Capability information that reflects only the codecs (Speech Versions) remaining after
-	 * intersecting MS, BSS and remote call leg restrictions. To store in trans for later use, and to include in
-	 * the outgoing CC Setup message. */
-	bearer_cap = (struct gsm_mncc_bearer_cap){
-		.speech_ver = { -1 },
-	};
-	sdp_audio_codecs_to_bearer_cap(&bearer_cap, &trans->cc.local.audio_codecs);
-	rc = bearer_cap_set_radio(&bearer_cap);
-	if (rc) {
-		LOG_TRANS(trans, LOGL_ERROR, "Error composing Bearer Capability for CC Setup\n");
-		trans_free(trans);
-		msgb_free(msg);
-		return rc;
+	/* Compose Bearer Capability information that reflects only the codecs (Speech Versions) / CSD bearer services
+	 * remaining after intersecting MS, BSS and remote call leg restrictions. To store in trans for later use, and
+	 * to include in the outgoing CC Setup message. */
+	switch (trans->bearer_cap.transfer) {
+	case GSM48_BCAP_ITCAP_SPEECH:
+		bearer_cap = (struct gsm_mncc_bearer_cap){
+			.speech_ver = { -1 },
+		};
+		sdp_audio_codecs_to_bearer_cap(&bearer_cap, &trans->cc.local.audio_codecs);
+		rc = bearer_cap_set_radio(&bearer_cap);
+		if (rc) {
+			LOG_TRANS(trans, LOGL_ERROR, "Error composing Bearer Capability for CC Setup\n");
+			trans_free(trans);
+			msgb_free(msg);
+			return rc;
+		}
+		/* If no resulting codecs remain, error out. We cannot find a codec that matches both call legs. If the MGW were
+		 * able to transcode, we could use non-identical codecs on each conn of the MGW endpoint, but we are aiming for
+		 * finding a matching codec. */
+		if (bearer_cap.speech_ver[0] == -1) {
+			LOG_TRANS(trans, LOGL_ERROR, "%s: no codec match possible: %s\n",
+				  get_mncc_name(setup->msg_type),
+				  codec_filter_to_str(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote));
+
+			/* incompatible codecs */
+			rc = mncc_release_ind(trans->net, trans, trans->callref,
+					      GSM48_CAUSE_LOC_PRN_S_LU,
+					      GSM48_CC_CAUSE_INCOMPAT_DEST /* TODO: correct cause code? */);
+			trans->callref = 0;
+			trans_free(trans);
+			msgb_free(msg);
+			return rc;
+		}
+		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		if (csd_bs_list_to_bearer_cap(&bearer_cap, &trans->cc.local.bearer_services) == 0) {
+			LOG_TRANS(trans, LOGL_ERROR, "Error composing Bearer Capability for CC Setup\n");
+
+			/* incompatible codecs */
+			rc = mncc_release_ind(trans->net, trans, trans->callref,
+					      GSM48_CAUSE_LOC_PRN_S_LU,
+					      GSM48_CC_CAUSE_INCOMPAT_DEST /* TODO: correct cause code? */);
+			trans->callref = 0;
+			trans_free(trans);
+			msgb_free(msg);
+			return rc;
+		}
+		break;
 	}
+
 	/* Create a copy of the bearer capability in the transaction struct, so we can use this information later */
 	trans->bearer_cap = bearer_cap;
-	/* If no resulting codecs remain, error out. We cannot find a codec that matches both call legs. If the MGW were
-	 * able to transcode, we could use non-identical codecs on each conn of the MGW endpoint, but we are aiming for
-	 * finding a matching codec. */
-	if (bearer_cap.speech_ver[0] == -1) {
-		LOG_TRANS(trans, LOGL_ERROR, "%s: no codec match possible: %s\n",
-			  get_mncc_name(setup->msg_type),
-			  codec_filter_to_str(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote));
 
-		/* incompatible codecs */
-		rc = mncc_release_ind(trans->net, trans, trans->callref,
-				      GSM48_CAUSE_LOC_PRN_S_LU,
-				      GSM48_CC_CAUSE_INCOMPAT_DEST /* TODO: correct cause code? */);
-		trans->callref = 0;
-		trans_free(trans);
-		msgb_free(msg);
-		return rc;
-	}
 	gsm48_encode_bearer_cap(msg, 0, &bearer_cap);
 
 	/* facility */
diff --git a/src/libmsc/msc_a.c b/src/libmsc/msc_a.c
index ca38206..11b242e 100644
--- a/src/libmsc/msc_a.c
+++ b/src/libmsc/msc_a.c
@@ -640,23 +640,48 @@
 	trans_cc_filter_run(cc_trans);
 	LOG_TRANS(cc_trans, LOGL_DEBUG, "Sending Assignment Command\n");
 
-	if (!cc_trans->cc.local.audio_codecs.count) {
-		LOG_TRANS(cc_trans, LOGL_ERROR, "Assignment not possible, no matching codec: %s\n",
-			  codec_filter_to_str(&cc_trans->cc.codecs, &cc_trans->cc.local, &cc_trans->cc.remote));
+	switch (cc_trans->bearer_cap.transfer) {
+	case GSM48_BCAP_ITCAP_SPEECH:
+		if (!cc_trans->cc.local.audio_codecs.count) {
+			LOG_TRANS(cc_trans, LOGL_ERROR, "Assignment not possible, no matching codec: %s\n",
+				  codec_filter_to_str(&cc_trans->cc.codecs, &cc_trans->cc.local, &cc_trans->cc.remote));
+			call_leg_release(msc_a->cc.call_leg);
+			return;
+		}
+
+		/* Compose 48.008 Channel Type from the current set of codecs
+		 * determined from both local and remote codec capabilities. */
+		if (sdp_audio_codecs_to_gsm0808_channel_type(&channel_type, &cc_trans->cc.local.audio_codecs)) {
+			LOG_MSC_A(msc_a, LOGL_ERROR, "Cannot compose Channel Type (Permitted Speech) from codecs: %s\n",
+				  codec_filter_to_str(&cc_trans->cc.codecs, &cc_trans->cc.local, &cc_trans->cc.remote));
+			trans_free(cc_trans);
+			return;
+		}
+		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		if (!cc_trans->cc.local.bearer_services.count) {
+			LOG_TRANS(cc_trans, LOGL_ERROR, "Assignment not possible, no matching bearer service: %s\n",
+				  csd_filter_to_str(&cc_trans->cc.csd, &cc_trans->cc.local, &cc_trans->cc.remote));
+			call_leg_release(msc_a->cc.call_leg);
+			return;
+		}
+
+		/* Compose 48.008 Channel Type from the current set of bearer
+		 * services determined from local and remote capabilities. */
+		if (csd_bs_list_to_gsm0808_channel_type(&channel_type, &cc_trans->cc.local.bearer_services)) {
+			LOG_MSC_A(msc_a, LOGL_ERROR, "Cannot compose channel type from: %s\n",
+				  csd_filter_to_str(&cc_trans->cc.csd, &cc_trans->cc.local, &cc_trans->cc.remote));
+			return;
+		}
+		break;
+	default:
+		LOG_TRANS(cc_trans, LOGL_ERROR, "Assignment not possible for information transfer capability %d\n",
+			  cc_trans->bearer_cap.transfer);
 		call_leg_release(msc_a->cc.call_leg);
 		return;
 	}
 
-	/* Compose 48.008 Channel Type from the current set of codecs determined from both local and remote codec
-	 * capabilities. */
-	if (sdp_audio_codecs_to_gsm0808_channel_type(&channel_type, &cc_trans->cc.local.audio_codecs)) {
-		LOG_MSC_A(msc_a, LOGL_ERROR, "Cannot compose Channel Type (Permitted Speech) from codecs: %s\n",
-			  codec_filter_to_str(&cc_trans->cc.codecs, &cc_trans->cc.local, &cc_trans->cc.remote));
-		trans_free(cc_trans);
-		return;
-	}
-
-	/* The RAN side RTP address is known, so the voice Assignment can commence. */
+	/* The RAN side RTP address is known, so the voice/CSD Assignment can commence. */
 	msg = (struct ran_msg){
 		.msg_type = RAN_MSG_ASSIGNMENT_COMMAND,
 		.assignment_command = {
diff --git a/src/libmsc/sdp_msg.c b/src/libmsc/sdp_msg.c
index d636222..cd721d3 100644
--- a/src/libmsc/sdp_msg.c
+++ b/src/libmsc/sdp_msg.c
@@ -657,6 +657,10 @@
 	OSMO_STRBUF_PRINTF(sb, OSMO_SOCKADDR_STR_FMT, OSMO_SOCKADDR_STR_FMT_ARGS(&sdp->rtp));
 	OSMO_STRBUF_PRINTF(sb, "{");
 	OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_to_str_buf, &sdp->audio_codecs);
+	if (sdp->bearer_services.count) {
+		OSMO_STRBUF_PRINTF(sb, ",");
+		OSMO_STRBUF_APPEND(sb, csd_bs_list_to_str_buf, &sdp->bearer_services);
+	}
 	OSMO_STRBUF_PRINTF(sb, "}");
 	return sb.chars_needed;
 }
@@ -670,3 +674,15 @@
 {
 	return sdp_msg_to_str_c(OTC_SELECT, sdp);
 }
+
+void sdp_audio_codecs_set_csd(struct sdp_audio_codecs *ac)
+{
+	*ac = (struct sdp_audio_codecs){
+		.count = 1,
+		.codec = {{
+			.payload_type = 120,
+			.subtype_name = "CLEARMODE",
+			.rate = 8000,
+		}},
+	};
+}
diff --git a/src/libmsc/transaction_cc.c b/src/libmsc/transaction_cc.c
index cb1424b..35ec5dc 100644
--- a/src/libmsc/transaction_cc.c
+++ b/src/libmsc/transaction_cc.c
@@ -24,32 +24,52 @@
 
 #include <osmocom/msc/transaction_cc.h>
 #include <osmocom/msc/codec_filter.h>
+#include <osmocom/msc/csd_filter.h>
 
 void trans_cc_filter_init(struct gsm_trans *trans)
 {
 	trans->cc.codecs = (struct codec_filter){};
+	trans->cc.csd = (struct csd_filter){};
 }
 
 void trans_cc_filter_set_ran(struct gsm_trans *trans, enum osmo_rat_type ran_type)
 {
 	codec_filter_set_ran(&trans->cc.codecs, ran_type);
+	csd_filter_set_ran(&trans->cc.csd, ran_type);
 }
 
 void trans_cc_filter_set_bss(struct gsm_trans *trans, struct msc_a *msc_a)
 {
 	codec_filter_set_bss(&trans->cc.codecs, &msc_a->cc.compl_l3_codec_list_bss_supported);
+
+	/* For CSD, there is no list of supported bearer services passed in
+	 * Complete Layer 3. TODO: make it configurable? */
 }
 
 void trans_cc_filter_run(struct gsm_trans *trans)
 {
-	codec_filter_run(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote);
-	LOG_TRANS(trans, LOGL_DEBUG, "codecs: %s\n",
-		  codec_filter_to_str(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote));
+	switch (trans->bearer_cap.transfer) {
+	case GSM48_BCAP_ITCAP_SPEECH:
+		codec_filter_run(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote);
+		LOG_TRANS(trans, LOGL_DEBUG, "codecs: %s\n",
+			  codec_filter_to_str(&trans->cc.codecs, &trans->cc.local, &trans->cc.remote));
+		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		csd_filter_run(&trans->cc.csd, &trans->cc.local, &trans->cc.remote);
+		LOG_TRANS(trans, LOGL_DEBUG, "codec/BS: %s\n",
+			  csd_filter_to_str(&trans->cc.csd, &trans->cc.local, &trans->cc.remote));
+		break;
+	default:
+		LOG_TRANS(trans, LOGL_ERROR, "Handling of information transfer capability %d not implemented\n",
+			  trans->bearer_cap.transfer);
+		break;
+	}
 }
 
 void trans_cc_filter_set_ms_from_bc(struct gsm_trans *trans, const struct gsm_mncc_bearer_cap *bcap)
 {
 	trans->cc.codecs.ms = (struct sdp_audio_codecs){0};
+	trans->cc.csd.ms = (struct csd_bs_list){0};
 
 	if (!bcap)
 		return;
@@ -58,6 +78,10 @@
 	case GSM48_BCAP_ITCAP_SPEECH:
 		sdp_audio_codecs_from_bearer_cap(&trans->cc.codecs.ms, bcap);
 		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		sdp_audio_codecs_set_csd(&trans->cc.codecs.ms);
+		csd_bs_list_from_bearer_cap(&trans->cc.csd.ms, bcap);
+		break;
 	default:
 		LOG_TRANS(trans, LOGL_ERROR, "Handling of information transfer capability %d not implemented\n",
 			  bcap->transfer);
@@ -68,6 +92,7 @@
 void trans_cc_set_remote_from_bc(struct gsm_trans *trans, const struct gsm_mncc_bearer_cap *bcap)
 {
 	trans->cc.remote.audio_codecs = (struct sdp_audio_codecs){0};
+	trans->cc.remote.bearer_services = (struct csd_bs_list){0};
 
 	if (!bcap)
 		return;
@@ -76,6 +101,10 @@
 	case GSM48_BCAP_ITCAP_SPEECH:
 		sdp_audio_codecs_from_bearer_cap(&trans->cc.remote.audio_codecs, bcap);
 		break;
+	case GSM48_BCAP_ITCAP_UNR_DIG_INF:
+		sdp_audio_codecs_set_csd(&trans->cc.remote.audio_codecs);
+		csd_bs_list_from_bearer_cap(&trans->cc.remote.bearer_services, bcap);
+		break;
 	default:
 		LOG_TRANS(trans, LOGL_ERROR, "Handling of information transfer capability %d not implemented\n",
 			  bcap->transfer);