3 files changed, 9 insertions, 6 deletions
diff --git a/src/common/includes/Core/fsm.h b/src/common/includes/Core/fsm.h
index 91bb231..ae12dae 100644
--- a/src/common/includes/Core/fsm.h
+++ b/src/common/includes/Core/fsm.h
@@ -117,7 +117,9 @@ void fsm_update(void);
 
 void fsm_balise_update(void);
 
-void fsm_sstv_update(void);
+// Update the FAX/SSTV state machine and return 1 if the 1750 notch filter must be
+// disabled
+int fsm_sstv_update(void);
 
 // Force a BALISE
 void fsm_balise_force(void);
diff --git a/src/common/src/Core/fsm.c b/src/common/src/Core/fsm.c
index c088fe0..2aaca3e 100644
--- a/src/common/src/Core/fsm.c
+++ b/src/common/src/Core/fsm.c
@@ -173,7 +173,7 @@ static const char* fsm_select_letter(void) {
     else if (fsm_in.qrp) {
         return letter_qrp;
     }
-    else if (fsm_in.fax_mode || sstv_state == SSTV_FSM_ON) {
+    else if (sstv_state == SSTV_FSM_ON) {
         return letter_sstv;
     }
 
@@ -636,7 +636,7 @@ void fsm_balise_update() {
     balise_state = next_state;
 }
 
-void fsm_sstv_update() {
+int fsm_sstv_update() {
 
     sstv_fsm_state_t next_state = sstv_state;
 
@@ -653,6 +653,7 @@ void fsm_sstv_update() {
             ) {
                 next_state = SSTV_FSM_OFF;
             }
+#warning "Disable FAX mode if 1750 is active for 5 seconds"
             break;
 
         default:
@@ -667,4 +668,5 @@ void fsm_sstv_update() {
 
     sstv_state = next_state;
 
+    return sstv_state == SSTV_FSM_ON;
 }
diff --git a/src/common/src/Core/main.c b/src/common/src/Core/main.c
index ec38df5..3f45f02 100644
--- a/src/common/src/Core/main.c
+++ b/src/common/src/Core/main.c
@@ -590,15 +590,14 @@ static void exercise_fsm(void __attribute__ ((unused))*pvParameters)
         fsm_input.det_1750 = tone_1750_status();
         pio_set_det_1750(fsm_input.det_1750);
         fsm_input.fax_mode = tone_fax_status();
-        pio_set_fax(fsm_input.fax_mode);
-
         fsm_input.swr_high = swr_error_flag;
         fsm_input.hour_is_even = hour_is_even;
 
         fsm_update_inputs(&fsm_input);
         fsm_update();
         fsm_balise_update();
-        fsm_sstv_update();
+        const int disable_1750_filter = fsm_sstv_update();
+        pio_set_fax(disable_1750_filter);
 
         struct fsm_output_signals_t fsm_out;
         fsm_get_outputs(&fsm_out);