diff --git a/daemon/codec.c b/daemon/codec.c
index 12d07b34e..a1acec066 100644
--- a/daemon/codec.c
+++ b/daemon/codec.c
@@ -37,9 +37,9 @@ struct mqtt_timer {
 };
 struct timer_callback {
 	struct codec_timer ct;
-	void (*timer_callback_func)(call_t *, void *);
+	void (*timer_callback_func)(call_t *, codec_timer_callback_arg_t);
 	call_t *call;
-	void *ptr;
+	codec_timer_callback_arg_t arg;
 };
 
 typedef void (*raw_input_func_t)(struct media_packet *mp, unsigned int);
@@ -5638,16 +5638,18 @@ static void __codec_timer_callback_free(void *p) {
 static void __codec_timer_callback_fire(struct codec_timer *ct) {
 	struct timer_callback *cb = (void *) ct;
 	log_info_call(cb->call);
-	cb->timer_callback_func(cb->call, cb->ptr);
+	cb->timer_callback_func(cb->call, cb->arg);
 	codec_timer_stop(&ct);
 	log_info_pop();
 }
-void codec_timer_callback(call_t *c, void (*func)(call_t *, void *), void *p, uint64_t delay) {
+void codec_timer_callback(call_t *c, void (*func)(call_t *, codec_timer_callback_arg_t),
+		codec_timer_callback_arg_t a, uint64_t delay)
+{
 	struct timer_callback *cb = obj_alloc0("codec_timer_callback", sizeof(*cb), __codec_timer_callback_free);
 	cb->ct.tt_obj.tt = &codec_timers_thread;
 	cb->call = obj_get(c);
 	cb->timer_callback_func = func;
-	cb->ptr = p;
+	cb->arg = a;
 	cb->ct.timer_func = __codec_timer_callback_fire;
 	cb->ct.next = rtpe_now;
 	timeval_add_usec(&cb->ct.next, delay);
diff --git a/daemon/dtmf.c b/daemon/dtmf.c
index 7247f1981..ab44188dd 100644
--- a/daemon/dtmf.c
+++ b/daemon/dtmf.c
@@ -264,8 +264,8 @@ void dtmf_trigger_set(struct call_monologue *ml, enum dtmf_trigger_type trigger_
 	state->inactive = inactive;
 }
 
-static void dtmf_trigger_set_block(call_t *c, void *mlp) {
-	struct call_monologue *ml = mlp;
+static void dtmf_trigger_set_block(call_t *c, codec_timer_callback_arg_t a) {
+	struct call_monologue *ml = a.ml;
 
 	rwlock_lock_w(&c->master_lock);
 
@@ -290,8 +290,8 @@ static void dtmf_trigger_set_block(call_t *c, void *mlp) {
 
 	rwlock_unlock_w(&c->master_lock);
 }
-static void dtmf_trigger_unset_block(call_t *c, void *mlp) {
-	struct call_monologue *ml = mlp;
+static void dtmf_trigger_unset_block(call_t *c, codec_timer_callback_arg_t a) {
+	struct call_monologue *ml = a.ml;
 
 	ilog(LOG_INFO, "Setting DTMF block mode to %i", ml->block_dtmf_trigger_end);
 
diff --git a/include/codec.h b/include/codec.h
index c345a730a..48f75aac0 100644
--- a/include/codec.h
+++ b/include/codec.h
@@ -89,12 +89,17 @@ struct codec_scheduler {
 	long output_skew;
 };
 
+typedef union {
+	struct call_monologue *ml;
+} codec_timer_callback_arg_t __attribute__ ((__transparent_union__));
+
 
 void codecs_init(void);
 void codecs_cleanup(void);
 void codec_timers_loop(void *);
 void rtcp_timer_stop(struct rtcp_timer **);
-void codec_timer_callback(call_t *, void (*)(call_t *, void *), void *, uint64_t delay);
+void codec_timer_callback(call_t *, void (*)(call_t *, codec_timer_callback_arg_t),
+		codec_timer_callback_arg_t, uint64_t delay);
 
 void mqtt_timer_stop(struct mqtt_timer **);
 void mqtt_timer_start(struct mqtt_timer **mqtp, call_t *call, struct call_media *media);