diff --git a/src/misc.c b/src/misc.c
index 2f5393dc..86bd34c5 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -366,7 +366,12 @@ void c_initialize_tables() {
     cpu65_vmem_r[0xC07F] =
         iie_check_dhires;
 
-    /* DHIRES/Annunciator switches */
+    /* Annunciator */
+    for (i = 0xC058; i <= 0xC05D; i++) {
+        cpu65_vmem_w[i] = cpu65_vmem_r[i] = iie_annunciator_noop;
+    }
+
+    /* DHIRES */
     cpu65_vmem_w[0xC05E] =
         cpu65_vmem_r[0xC05E] =
             iie_dhires_on;
diff --git a/src/misc.h b/src/misc.h
index 83da452b..576e8ab3 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -204,6 +204,7 @@ iie_cxrom_peripheral(),
 iie_cxrom_internal(),
 iie_ioudis_on(),
 iie_ioudis_off(),
+iie_annunciator_noop(),
 iie_dhires_on(),
 iie_dhires_off(),
 iie_hires_off(),
diff --git a/src/vm.c b/src/vm.c
index e7c4d1bb..5683d4d8 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -265,6 +265,11 @@ GLUE_C_READ(iie_check_mixed)
     return (softswitches & SS_MIXED) ? 0x80 : 0x00;
 }
 
+GLUE_C_READ(iie_annunciator_noop)
+{
+    return 0x0;// TBD : mem_floating_bus()
+}
+
 GLUE_C_READ(iie_hires_off)
 {
     if (!(softswitches & SS_HIRES)) {