diff --git a/src/codec/gsm690.c b/src/codec/gsm690.c
index 1955716..8ab1df1 100644
--- a/src/codec/gsm690.c
+++ b/src/codec/gsm690.c
@@ -216,8 +216,9 @@
 	 92,  31,  52,  65,  86,
 };
 
+/* See also RFC 4867 §3.6, Table 1, Column "Total speech bits" */
 static const uint8_t amr_len_by_ft[16] = {
-	12, 13, 15, 17, 19, 20, 26, 31, 7,  0,  0,  0,  0,  0,  0,  0
+	12, 13, 15, 17, 19, 20, 26, 31, 5,  0,  0,  0,  0,  0,  0,  0
 };
 
 const struct value_string osmo_amr_type_names[] = {
diff --git a/tests/codec/codec_test.ok b/tests/codec/codec_test.ok
index 5307023..b8cba19 100644
--- a/tests/codec/codec_test.ok
+++ b/tests/codec/codec_test.ok
@@ -1,6 +1,6 @@
 AMR RTP payload decoder test:
-[9] decode RTP 20 44 00 00 00 00 04 OK: FT AMR SID, CMR AMR 5,90 kbit/s, CMI is 2, SID type FIRST	[9] encode [0]
-[9] decode RTP 20 44 29 c2 92 91 f4 OK: FT AMR SID, CMR AMR 5,90 kbit/s, CMI is 2, SID type UPDATE	[9] encode [0]
+[7] decode RTP 20 44 00 00 00 00 04 OK: FT AMR SID, CMR AMR 5,90 kbit/s, CMI is 2, SID type FIRST	[7] encode [0]
+[7] decode RTP 20 44 29 c2 92 91 f4 OK: FT AMR SID, CMR AMR 5,90 kbit/s, CMI is 2, SID type UPDATE	[7] encode [0]
 [2/2] No Data/NA, CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1
 [2/2] No Data/NA, CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1
 [33/33] AMR 12,2 kbit/s (GSM-EFR), CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1