diff --git a/lib_com/ivas_cnst.h b/lib_com/ivas_cnst.h
index b950fe51e7bc4685c29c04b9b350e2852bb52dc8..2a09295cb3199381b63872de7ba93d911a4c591d 100755
--- a/lib_com/ivas_cnst.h
+++ b/lib_com/ivas_cnst.h
@@ -313,6 +313,9 @@ typedef enum
 #define MIN_BRATE_SWB_SCE                       ACELP_9k60                  /* min. SCE bitrate where SWB is supported */
 #define MIN_BRATE_SWB_STEREO                    IVAS_13k2                   /* min. stereo bitrate where SWB is supported */
 #define MIN_BRATE_FB_STEREO                     IVAS_32k                    /* min. SCE and stereo bitrate where FB is supported */
+#ifdef ISM_FB
+#define MIN_BRATE_FB_ISM                        24000                       /* min. SCE bitrate where FB is supported in ISM format */
+#endif
 
 #define MIN_TDM_BRATE_WB_TBE_1k05               12000                       /* min. per channel bitrate where WB TBE @1.05 kbps is supported (0.35kbs at lower bitrates) */
 #define MIN_BRATE_WB_TBE_1k05                   9650                        /* min. per channel bitrate where WB TBE @1.05 kbps is supported (0.35kbs at lower bitrates) */
diff --git a/lib_com/options.h b/lib_com/options.h
index b57e3c1db0178d9c3e1eab19d430e05455811d7a..7ac8448cf859d4c8c9bd5c73ea047e21be10c514 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -159,10 +159,10 @@
 
 #define IGF_TUNING_96                                   /* FhG: Issue 546: slight tuning of IGF config used in 96 kbps stereo, 128 kbps SBA and others */
 #define FIX_549_DMX_GAIN                                /* FhG: issue 549: ParamISM output too quiet */
-
 #define FIX_522_ISM_FIRST_SID                           /* VA: fix ISM decoder crash if first received frame is an SID */
-
 #define FIX_470_MASA_JBM_EXT                            /* Nokia: Issue 470, fix MASA EXT output with JBM */
+#define ISM_FB                                          /* issue 556: change SWB to FB coding in 1ISM at 24.4 kbps */
+
 
 /* ################## End DEVELOPMENT switches ######################### */
 /* clang-format on */
diff --git a/lib_dec/ivas_sce_dec.c b/lib_dec/ivas_sce_dec.c
index e1472d2a37eccf0d692b0e33c2ff052b956ef7c5..f42f309ac9d366297aa17d8d94684e228eb639ad 100755
--- a/lib_dec/ivas_sce_dec.c
+++ b/lib_dec/ivas_sce_dec.c
@@ -123,7 +123,12 @@ ivas_error ivas_sce_dec(
             /* only WB is supported */
             st->bwidth = WB;
         }
+#ifdef ISM_FB
+        else if ( ( hSCE->element_brate < MIN_BRATE_FB_STEREO && !st->is_ism_format ) ||
+                  ( hSCE->element_brate < MIN_BRATE_FB_ISM && st->is_ism_format ) )
+#else
         else if ( hSCE->element_brate < MIN_BRATE_FB_STEREO )
+#endif
         {
             /* WB and SWB are supported */
             st->bwidth = get_next_indice( st, 1 ) + WB;
diff --git a/lib_enc/bw_detect.c b/lib_enc/bw_detect.c
index 9c96a851f212f58afc37d5670a6b6b2b17e75ed0..4c4df2fe948af04f77735512fa872e4bc34d9e76 100644
--- a/lib_enc/bw_detect.c
+++ b/lib_enc/bw_detect.c
@@ -587,7 +587,12 @@ void set_bw(
             {
                 st->bwidth = WB;
             }
+#ifdef ISM_FB
+            else if ( st->bwidth > SWB && ( ( element_brate < MIN_BRATE_FB_STEREO && !st->is_ism_format ) ||
+                                            ( element_brate < MIN_BRATE_FB_ISM && st->is_ism_format ) ) )
+#else
             else if ( element_brate < MIN_BRATE_FB_STEREO && st->bwidth > SWB )
+#endif
             {
                 st->bwidth = SWB;
             }
diff --git a/lib_enc/ivas_decision_matrix_enc.c b/lib_enc/ivas_decision_matrix_enc.c
index 8f3a9de2f1c09830847f8db5e61a018cc73e59c6..65f16a4a28915bceb4f91693abc45c998fbde692 100644
--- a/lib_enc/ivas_decision_matrix_enc.c
+++ b/lib_enc/ivas_decision_matrix_enc.c
@@ -434,7 +434,12 @@ void ivas_signaling_enc(
             {
                 /* only WB is supported */
             }
+#ifdef ISM_FB
+            else if ( ( element_brate < MIN_BRATE_FB_STEREO && !st->is_ism_format ) ||
+                      ( element_brate < MIN_BRATE_FB_ISM && st->is_ism_format ) )
+#else
             else if ( element_brate < MIN_BRATE_FB_STEREO )
+#endif
             {
                 /* WB and SWB are supported */
                 ind = st->bwidth - WB;
diff --git a/lib_enc/lib_enc.c b/lib_enc/lib_enc.c
index bb8eeadc5f32b8eec57c030fea48851a1a45559d..8316fd381dd15fb00df653430e4175e5a4739677 100644
--- a/lib_enc/lib_enc.c
+++ b/lib_enc/lib_enc.c
@@ -1699,7 +1699,16 @@ static ivas_error printConfigInfo_enc(
     {
         if ( newBandwidthApi != hEncoderConfig->max_bwidth )
         {
-            fprintf( stdout, "\nFB coding not supported below %.2f kbps. Switching to SWB.\n", MIN_BRATE_FB_STEREO / 1000.f );
+#ifdef ISM_FB
+            if ( hEncoderConfig->ivas_format == ISM_FORMAT )
+            {
+                fprintf( stdout, "\nFB coding not supported below %.2f kbps for %i objects. Switching to SWB.\n", hEncoderConfig->nchan_ism * MIN_BRATE_FB_ISM / 1000.f, hEncoderConfig->nchan_ism );
+            }
+            else
+#endif
+            {
+                fprintf( stdout, "\nFB coding not supported below %.2f kbps. Switching to SWB.\n", MIN_BRATE_FB_STEREO / 1000.f );
+            }
         }
     }
 
@@ -1996,7 +2005,12 @@ static ivas_error sanitizeBandwidth(
     }
     else
     {
+#ifdef ISM_FB
+        if ( max_bwidth_tmp == FB && ( ( hEncoderConfig->ivas_format != ISM_FORMAT && hEncoderConfig->ivas_total_brate < MIN_BRATE_FB_STEREO ) ||
+                                       ( hEncoderConfig->ivas_format == ISM_FORMAT && hEncoderConfig->ivas_total_brate / hEncoderConfig->nchan_ism < MIN_BRATE_FB_ISM ) ) )
+#else
         if ( max_bwidth_tmp == FB && hEncoderConfig->ivas_total_brate < MIN_BRATE_FB_STEREO )
+#endif
         {
             max_bwidth_tmp = SWB;
         }