diff --git a/rigs/dummy/aclog.c b/rigs/dummy/aclog.c
index 8596d5c87..77a382801 100644
--- a/rigs/dummy/aclog.c
+++ b/rigs/dummy/aclog.c
@@ -738,7 +738,7 @@ static int aclog_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
     char cmd[MAXCMDLEN];
     char *p;
     char *pttmode;
-    char *ttmode;
+    char *ttmode = NULL;
     struct aclog_priv_data *priv = (struct aclog_priv_data *) rig->state.priv;
 
     ENTERFUNC;
diff --git a/rigs/dummy/flrig.c b/rigs/dummy/flrig.c
index bc5964043..5c793539d 100644
--- a/rigs/dummy/flrig.c
+++ b/rigs/dummy/flrig.c
@@ -1374,7 +1374,7 @@ static int flrig_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
     char cmd_arg[MAXCMDLEN];
     char *p;
     char *pttmode;
-    char *ttmode;
+    char *ttmode = NULL;
     struct flrig_priv_data *priv = (struct flrig_priv_data *) rig->state.priv;
 
     ENTERFUNC;
diff --git a/rigs/dummy/sdrsharp.c b/rigs/dummy/sdrsharp.c
index e47f694cb..530fb9b07 100644
--- a/rigs/dummy/sdrsharp.c
+++ b/rigs/dummy/sdrsharp.c
@@ -387,6 +387,8 @@ static int sdrsharp_open(RIG *rig)
     char value[MAXARGLEN];
 
     ENTERFUNC;
+    value[0] = '?';
+    value[1] = 0;
 
     freq_t freq;
     retval = sdrsharp_get_freq(rig, RIG_VFO_CURR, &freq);
diff --git a/rigs/dummy/tci1x.c b/rigs/dummy/tci1x.c
index 2fe040e0d..39bcaa19b 100644
--- a/rigs/dummy/tci1x.c
+++ b/rigs/dummy/tci1x.c
@@ -596,6 +596,8 @@ static int tci1x_open(RIG *rig)
     char *p;
     char *pr;
     //struct tci1x_priv_data *priv = (struct tci1x_priv_data *) rig->state.priv;
+    arg[0] = '?';
+    arg[1] = 0;
 
     rig_debug(RIG_DEBUG_VERBOSE, "%s: version %s\n", __func__, rig->caps->version);
     char *websocket =
@@ -1097,7 +1099,7 @@ static int tci1x_set_mode(RIG *rig, vfo_t vfo, rmode_t mode, pbwidth_t width)
     char cmd_arg[MAXCMDLEN];
     char *p;
     char *pttmode;
-    char *ttmode;
+    char *ttmode = NULL;
     struct tci1x_priv_data *priv = (struct tci1x_priv_data *) rig->state.priv;
 
     ENTERFUNC;