diff --git a/include/osmocom/gsm/gsm0808_utils.h b/include/osmocom/gsm/gsm0808_utils.h
index 53f145c..dedb029 100644
--- a/include/osmocom/gsm/gsm0808_utils.h
+++ b/include/osmocom/gsm/gsm0808_utils.h
@@ -130,7 +130,7 @@
 int gsm0808_speech_codec_from_chan_type(struct gsm0808_speech_codec *sc,
 					uint8_t perm_spch);
 uint16_t gsm0808_sc_cfg_from_gsm48_mr_cfg(const struct gsm48_multi_rate_conf *cfg, bool fr);
-void gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg, uint16_t s15_s0);
+int gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg, uint16_t s15_s0);
 
 /*! \returns 3GPP TS 08.08 §3.2.2.5 Class of a given Cause */
 static inline enum gsm0808_cause_class gsm0808_cause_class(enum gsm0808_cause cause)
diff --git a/include/osmocom/gsm/protocol/gsm_08_08.h b/include/osmocom/gsm/protocol/gsm_08_08.h
index 67dc6ee..aa01ee5 100644
--- a/include/osmocom/gsm/protocol/gsm_08_08.h
+++ b/include/osmocom/gsm/protocol/gsm_08_08.h
@@ -553,6 +553,20 @@
 	GSM0808_SC_CFG_DEFAULT_AMR_12_2 = 0xc082
 };
 
+/*! Single speech codec configurations broken down by reate.
+ *  See also: 3GPP TS 28.062, Table 7.11.3.1.3-2: Preferred Configurations for
+ *  the Adaptive Multi-Rate Codec Types. */
+enum gsm0808_speech_codec_rate {
+	GSM0808_SC_CFG_AMR_4_75 = 0x0001,
+	GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20 = 0x0002,
+	GSM0808_SC_CFG_AMR_5_90 = 0x0004,
+	GSM0808_SC_CFG_AMR_6_70 = 0x0008,
+	GSM0808_SC_CFG_AMR_7_40 = 0x0010,
+	GSM0808_SC_CFG_AMR_7_95 = 0x0020,
+	GSM0808_SC_CFG_AMR_10_2 = 0x0040,
+	GSM0808_SC_CFG_AMR_12_2 = 0x0080,
+};
+
 /* 3GPP TS 48.008 3.2.2.103 Speech Codec List */
 #define SPEECH_CODEC_MAXLEN 255
 struct gsm0808_speech_codec_list {
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index dd14d3c..2552c08 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -1346,42 +1346,94 @@
 /*! Determine a GSM 04.08 AMR configuration struct from a set of speech codec
  *  configuration bits (S0-S15)
  *  \param[out] cfg AMR configuration in GSM 04.08 format.
- *  \param[in] s15_s0 configuration bits (S0-S15). */
-void gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg,
-				      uint16_t s15_s0)
+ *  \param[in] s15_s0 configuration bits (S15-S0, non-ambiguous).
+ *  \returns zero when successful; negative on error */
+int gsm48_mr_cfg_from_gsm0808_sc_cfg(struct gsm48_multi_rate_conf *cfg,
+				     uint16_t s15_s0)
 {
+	unsigned int count = 0;
+
+	/* Note: See also: 3GPP TS 28.062
+	 * Table 7.11.3.1.3-2: Preferred Configurations for the Adaptive
+	 * Multi-Rate Codec Types */
+
+	/* Note: The resulting multirate-configuration must not contain an
+	 * active set of more than four codec rates. The active set also
+	 * must contain at least one rate. */
+
 	memset(cfg, 0, sizeof(*cfg));
+	cfg->ver = 1;
+	cfg->icmi = 1;
 
 	/* Strip option bits */
 	s15_s0 &= 0x00ff;
 
-	/* Rate 5,15k must always be present */
-	cfg->m5_15 = 1;
+	/* Rate 5,15k can never be selected (see table) */
+	cfg->m5_15 = 0;
 
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_4_75 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_4_75 & 0xff))
+	if (s15_s0 & GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20 & 0xff) {
+		/* Table Table 7.11.3.1.3-2 lists one mode that selects 4
+		 * rates at once (Config-NB-Code = 1). The rates selected
+		 * are known to be compatible between GERAN and UTRAN, since
+		 * an active set must not contain more than four rates at
+		 * a time, we ignore all other settings as they are either
+		 * redundaned or excess settings (invalid) */
 		cfg->m4_75 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_5_90 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_5_90 & 0xff))
 		cfg->m5_90 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_6_70 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_6_70 & 0xff))
-		cfg->m6_70 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_7_40 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_7_40 & 0xff))
 		cfg->m7_40 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_7_95 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_7_95 & 0xff))
-		cfg->m7_95 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_10_2 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_10_2 & 0xff))
-		cfg->m10_2 = 1;
-	if ((s15_s0 & GSM0808_SC_CFG_DEFAULT_AMR_12_2 & 0xff) ==
-	    (GSM0808_SC_CFG_DEFAULT_AMR_12_2 & 0xff))
 		cfg->m12_2 = 1;
+		count += 4;
+	}
 
-	cfg->ver = 1;
-	cfg->icmi = 1;
+	/* Check the bits in s15_s0 and set the flags for the
+	 * respective rates. */
+	if (s15_s0 & GSM0808_SC_CFG_AMR_4_75 && !cfg->m4_75) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m4_75 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_5_90 && !cfg->m5_90) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m5_90 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_6_70) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m6_70 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_7_40 && !cfg->m7_40) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m7_40 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_7_95) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m7_95 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_10_2) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m10_2 = 1;
+		count++;
+	}
+	if (s15_s0 & GSM0808_SC_CFG_AMR_12_2 && !cfg->m12_2) {
+		if (count >= 4)
+			return -EINVAL;
+		cfg->m12_2 = 1;
+		count++;
+	}
+
+	if (count == 0)
+		return -EINVAL;
+
+	return 0;
 }
 
 int gsm0808_get_cipher_reject_cause(const struct tlv_parsed *tp)
diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c
index c448f43..87f5d2a 100644
--- a/tests/gsm0808/gsm0808_test.c
+++ b/tests/gsm0808/gsm0808_test.c
@@ -1907,12 +1907,13 @@
 static void test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(uint16_t s15_s0)
 {
 	struct gsm48_multi_rate_conf cfg;
+	int rc;
 
 	printf("Input:\n");
 	printf(" S15-S0 = %04x = 0b" OSMO_BIN_SPEC OSMO_BIN_SPEC "\n", s15_s0,
 	       OSMO_BIN_PRINT(s15_s0 >> 8), OSMO_BIN_PRINT(s15_s0));
 
-	gsm48_mr_cfg_from_gsm0808_sc_cfg(&cfg, s15_s0);
+	rc = gsm48_mr_cfg_from_gsm0808_sc_cfg(&cfg, s15_s0);
 
 	printf("Output:\n");
 	printf(" m4_75= %u   smod=  %u\n", cfg.m4_75, cfg.smod);
@@ -1924,6 +1925,9 @@
 	printf(" m10_2= %u\n", cfg.m10_2);
 	printf(" m12_2= %u\n", cfg.m12_2);
 
+	if (rc != 0)
+		printf(" Result invalid!\n");
+
 	printf("\n");
 }
 
@@ -1931,7 +1935,8 @@
 {
 	printf("Testing gsm48_mr_cfg_from_gsm0808_sc_cfg():\n");
 
-	/* Only one codec per setting */
+	/* Test with settings as defined in 3GPP TS 28.062, Table 7.11.3.1.3-2,
+	 * (up to four codecs may become selected) */
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
 	    (GSM0808_SC_CFG_DEFAULT_AMR_4_75);
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
@@ -1949,15 +1954,40 @@
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
 	    (GSM0808_SC_CFG_DEFAULT_AMR_12_2);
 
-	/* Combinations */
+	/* Test with settings as defined in 3GPP TS 28.062, Table 7.11.3.1.3-2,
+	 * but pick only one distinctive setting at a time */
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_4_75);
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
-	    (GSM0808_SC_CFG_DEFAULT_AMR_4_75 | GSM0808_SC_CFG_DEFAULT_AMR_6_70 |
-	     GSM0808_SC_CFG_DEFAULT_AMR_10_2);
+	    (GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_5_90);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_6_70);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_7_40);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_7_95);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_10_2);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_12_2);
+
+	/* Arbitrary, but valid combinations */
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_7_40 |
+						     GSM0808_SC_CFG_AMR_6_70 |
+						     GSM0808_SC_CFG_AMR_10_2);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_7_95 |
+						     GSM0808_SC_CFG_AMR_4_75);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_5_90 |
+						     GSM0808_SC_CFG_AMR_12_2);
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
-	    (GSM0808_SC_CFG_DEFAULT_AMR_10_2 | GSM0808_SC_CFG_DEFAULT_AMR_12_2 |
-	     GSM0808_SC_CFG_DEFAULT_AMR_7_40);
+	    (GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20 | GSM0808_SC_CFG_AMR_5_90 |
+	     GSM0808_SC_CFG_AMR_12_2);
+
+	/* Invalid combinations */
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single
-	    (GSM0808_SC_CFG_DEFAULT_AMR_7_95 | GSM0808_SC_CFG_DEFAULT_AMR_12_2);
+	    (GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20 | GSM0808_SC_CFG_AMR_6_70);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(GSM0808_SC_CFG_AMR_7_40 |
+						     GSM0808_SC_CFG_AMR_6_70 |
+						     GSM0808_SC_CFG_AMR_10_2 |
+						     GSM0808_SC_CFG_AMR_7_95 |
+						     GSM0808_SC_CFG_AMR_4_75);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(0x0000);
+	test_gsm48_mr_cfg_from_gsm0808_sc_cfg_single(0xffff);
 }
 
 struct test_cell_id_matching_data {
@@ -2359,7 +2389,6 @@
 	test_gsm0808_enc_dec_cell_id_ci();
 	test_gsm0808_enc_dec_cell_id_lac_and_ci();
 	test_gsm0808_enc_dec_cell_id_global();
-
 	test_gsm0808_sc_cfg_from_gsm48_mr_cfg();
 	test_gsm48_mr_cfg_from_gsm0808_sc_cfg();
 
diff --git a/tests/gsm0808/gsm0808_test.ok b/tests/gsm0808/gsm0808_test.ok
index 6035326..9fce0e8 100644
--- a/tests/gsm0808/gsm0808_test.ok
+++ b/tests/gsm0808/gsm0808_test.ok
@@ -315,43 +315,44 @@
  S15-S0 = ff03 = 0b1111111100000011
 Output:
  m4_75= 1   smod=  0
- m5_15= 1   spare= 0
- m5_90= 0   icmi=  1
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
  m6_70= 0   nscb=  0
- m7_40= 0   ver=   1
+ m7_40= 1   ver=   1
  m7_95= 0
  m10_2= 0
- m12_2= 0
+ m12_2= 1
 
 Input:
  S15-S0 = 0000 = 0b0000000000000000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 0   nscb=  0
  m7_40= 0   ver=   1
  m7_95= 0
  m10_2= 0
  m12_2= 0
+ Result invalid!
 
 Input:
  S15-S0 = ff06 = 0b1111111100000110
 Output:
- m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
  m5_90= 1   icmi=  1
  m6_70= 0   nscb=  0
- m7_40= 0   ver=   1
+ m7_40= 1   ver=   1
  m7_95= 0
  m10_2= 0
- m12_2= 0
+ m12_2= 1
 
 Input:
  S15-S0 = 3e08 = 0b0011111000001000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 1   nscb=  0
  m7_40= 0   ver=   1
@@ -362,20 +363,20 @@
 Input:
  S15-S0 = 0c12 = 0b0000110000010010
 Output:
- m4_75= 0   smod=  0
- m5_15= 1   spare= 0
- m5_90= 0   icmi=  1
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
  m6_70= 0   nscb=  0
  m7_40= 1   ver=   1
  m7_95= 0
  m10_2= 0
- m12_2= 0
+ m12_2= 1
 
 Input:
  S15-S0 = c020 = 0b1100000000100000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 0   nscb=  0
  m7_40= 0   ver=   1
@@ -387,7 +388,7 @@
  S15-S0 = 3040 = 0b0011000001000000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 0   nscb=  0
  m7_40= 0   ver=   1
@@ -398,51 +399,211 @@
 Input:
  S15-S0 = c082 = 0b1100000010000010
 Output:
- m4_75= 0   smod=  0
- m5_15= 1   spare= 0
- m5_90= 0   icmi=  1
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
  m6_70= 0   nscb=  0
- m7_40= 0   ver=   1
+ m7_40= 1   ver=   1
  m7_95= 0
  m10_2= 0
  m12_2= 1
 
 Input:
- S15-S0 = ff4b = 0b1111111101001011
+ S15-S0 = 0001 = 0b0000000000000001
 Output:
  m4_75= 1   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0002 = 0b0000000000000010
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 1
+
+Input:
+ S15-S0 = 0004 = 0b0000000000000100
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0008 = 0b0000000000001000
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 1   nscb=  0
  m7_40= 0   ver=   1
  m7_95= 0
+ m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0010 = 0b0000000000010000
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0020 = 0b0000000000100000
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 1
+ m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0040 = 0b0000000001000000
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 0
  m10_2= 1
  m12_2= 0
 
 Input:
- S15-S0 = fcd2 = 0b1111110011010010
+ S15-S0 = 0080 = 0b0000000010000000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 0   nscb=  0
- m7_40= 1   ver=   1
+ m7_40= 0   ver=   1
  m7_95= 0
- m10_2= 1
+ m10_2= 0
  m12_2= 1
 
 Input:
- S15-S0 = c0a2 = 0b1100000010100010
+ S15-S0 = 0058 = 0b0000000001011000
 Output:
  m4_75= 0   smod=  0
- m5_15= 1   spare= 0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 1   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 1
+ m12_2= 0
+
+Input:
+ S15-S0 = 0021 = 0b0000000000100001
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
  m5_90= 0   icmi=  1
  m6_70= 0   nscb=  0
  m7_40= 0   ver=   1
  m7_95= 1
  m10_2= 0
+ m12_2= 0
+
+Input:
+ S15-S0 = 0084 = 0b0000000010000100
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 0
+ m10_2= 0
  m12_2= 1
 
+Input:
+ S15-S0 = 0086 = 0b0000000010000110
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 1
+
+Input:
+ S15-S0 = 000a = 0b0000000000001010
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 1
+ Result invalid!
+
+Input:
+ S15-S0 = 0079 = 0b0000000001111001
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 1   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 1
+ m10_2= 0
+ m12_2= 0
+ Result invalid!
+
+Input:
+ S15-S0 = 0000 = 0b0000000000000000
+Output:
+ m4_75= 0   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 0   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 0   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 0
+ Result invalid!
+
+Input:
+ S15-S0 = ffff = 0b1111111111111111
+Output:
+ m4_75= 1   smod=  0
+ m5_15= 0   spare= 0
+ m5_90= 1   icmi=  1
+ m6_70= 0   nscb=  0
+ m7_40= 1   ver=   1
+ m7_95= 0
+ m10_2= 0
+ m12_2= 1
+ Result invalid!
+
 
 test_cell_id_matching
 [0] LAC:23 LAC:23 MATCH