diff --git a/src/anetz/anetz.c b/src/anetz/anetz.c
index 2858982..0024f42 100644
--- a/src/anetz/anetz.c
+++ b/src/anetz/anetz.c
@@ -202,7 +202,7 @@ static void anetz_go_idle(anetz_t *anetz)
 
 	PDEBUG(DANETZ, DEBUG_INFO, "Entering IDLE state, sending 2280 Hz tone.\n");
 	anetz->state = ANETZ_FREI;
-	anetz->dsp_mode = DSP_MODE_TONE;
+	anetz_set_dsp_mode(anetz, DSP_MODE_TONE);
 	anetz->station_id[0] = '\0';
 }
 
@@ -213,7 +213,7 @@ static void anetz_release(anetz_t *anetz)
 
 	PDEBUG(DANETZ, DEBUG_INFO, "Sending 2280 Hz release tone.\n");
 	anetz->state = ANETZ_AUSLOESEN;
-	anetz->dsp_mode = DSP_MODE_TONE;
+	anetz_set_dsp_mode(anetz, DSP_MODE_TONE);
 	anetz->station_id[0] = '\0';
 	timer_start(&anetz->timer, RELEASE_TO);
 }
@@ -223,7 +223,7 @@ static void anetz_page(anetz_t *anetz, const char *dial_string, double *freq)
 {
 	PDEBUG(DANETZ, DEBUG_INFO, "Entering paging state, sending 'Selektivruf' to '%s'.\n", dial_string);
 	anetz->state = ANETZ_ANRUF;
-	anetz->dsp_mode = DSP_MODE_PAGING;
+	anetz_set_dsp_mode(anetz, DSP_MODE_PAGING);
 	dsp_set_paging(anetz, freq);
 	strcpy(anetz->station_id, dial_string);
 	timer_start(&anetz->timer, PAGING_TO);
@@ -262,7 +262,7 @@ void anetz_receive_tone(anetz_t *anetz, int tone)
 		if (tone == 1) {
 			PDEBUG(DANETZ, DEBUG_INFO, "Received 1750 Hz calling signal from mobile station, removing idle signal.\n");
 			anetz->state = ANETZ_GESPRAECH;
-			anetz->dsp_mode = DSP_MODE_SILENCE;
+			anetz_set_dsp_mode(anetz, DSP_MODE_SILENCE);
 			break;
 		}
 		break;
@@ -285,7 +285,7 @@ void anetz_receive_tone(anetz_t *anetz, int tone)
 				PDEBUG(DANETZ, DEBUG_INFO, "1750 Hz signal from mobile station is gone, answer call.\n");
 				call_in_answer(anetz->sender.callref, anetz->station_id);
 			}
-			anetz->dsp_mode = DSP_MODE_AUDIO;
+			anetz_set_dsp_mode(anetz, DSP_MODE_AUDIO);
 		}
 		/* release call */
 		if (tone == 1) {
@@ -302,7 +302,7 @@ void anetz_receive_tone(anetz_t *anetz, int tone)
 			PDEBUG(DANETZ, DEBUG_INFO, "Received 1750 Hz answer signal from mobile station, removing paging tones.\n");
 			timer_stop(&anetz->timer);
 			anetz->state = ANETZ_GESPRAECH;
-			anetz->dsp_mode = DSP_MODE_SILENCE;
+			anetz_set_dsp_mode(anetz, DSP_MODE_SILENCE);
 			break;
 		}
 	default:
diff --git a/src/anetz/dsp.c b/src/anetz/dsp.c
index 90277be..aed2334 100644
--- a/src/anetz/dsp.c
+++ b/src/anetz/dsp.c
@@ -349,3 +349,9 @@ void sender_send(sender_t *sender, int16_t *samples, int length)
 	}
 }
 
+void anetz_set_dsp_mode(anetz_t *anetz, enum dsp_mode mode)
+{
+	PDEBUG(DDSP, DEBUG_DEBUG, "DSP mode %d -> %d\n", anetz->dsp_mode, mode);
+	anetz->dsp_mode = mode;
+}
+
diff --git a/src/anetz/dsp.h b/src/anetz/dsp.h
index b544ad5..890fee4 100644
--- a/src/anetz/dsp.h
+++ b/src/anetz/dsp.h
@@ -3,4 +3,5 @@ void dsp_init(void);
 int dsp_init_sender(anetz_t *anetz);
 void dsp_cleanup_sender(anetz_t *anetz);
 void dsp_set_paging(anetz_t *anetz, double *freq);
+void anetz_set_dsp_mode(anetz_t *anetz, enum dsp_mode mode);
 
diff --git a/src/bnetz/dsp.c b/src/bnetz/dsp.c
index 08efa48..375abca 100644
--- a/src/bnetz/dsp.c
+++ b/src/bnetz/dsp.c
@@ -412,6 +412,8 @@ void bnetz_set_dsp_mode(bnetz_t *bnetz, enum dsp_mode mode)
 	/* reset telegramm */
 	if (mode == DSP_MODE_TELEGRAMM && bnetz->dsp_mode != mode)
 		bnetz->telegramm = 0;
+	
+	PDEBUG(DDSP, DEBUG_DEBUG, "DSP mode %d -> %d\n", bnetz->dsp_mode, mode);
 	bnetz->dsp_mode = mode;
 }
 
diff --git a/src/cnetz/cnetz.c b/src/cnetz/cnetz.c
index 2ccffa6..07ae2e4 100644
--- a/src/cnetz/cnetz.c
+++ b/src/cnetz/cnetz.c
@@ -221,23 +221,21 @@ int cnetz_create(int kanal, enum cnetz_chan_type chan_type, const char *sounddev
 		goto error;
 
 	/* go into idle state */
-	cnetz->dsp_mode = DSP_MODE_OGK;
-	cnetz->sched_dsp_mode = DSP_MODE_OGK;
-	cnetz->sched_switch_mode = 0;
+	cnetz_set_dsp_mode(cnetz, DSP_MODE_OGK);
+	cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_OGK, 0);
 	cnetz_go_idle(cnetz);
 
 #ifdef DEBUG_SPK
 	transaction_t *trans = create_transaction(cnetz, TRANS_DS, 2, 2, 22002);
 	trans->mo_call = 1;
-	cnetz->sched_switch_mode = 2;
-	cnetz->sched_dsp_mode = DSP_MODE_SPK_K;
+	cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_SPK_K, 2);
 #else
 	/* create transaction for speech channel loopback */
 	if (loopback && chan_type == CHAN_TYPE_SPK) {
 		transaction_t *trans = create_transaction(cnetz, TRANS_VHQ, 2, 2, 22002);
 		trans->mo_call = 1;
-		cnetz->dsp_mode = DSP_MODE_SPK_K;
-		cnetz->sched_dsp_mode = DSP_MODE_SPK_K;
+		cnetz_set_dsp_mode(cnetz, DSP_MODE_SPK_K);
+		cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_SPK_K, 0);
 	}
 #endif
 
@@ -282,11 +280,10 @@ static void cnetz_go_idle(cnetz_t *cnetz)
 	cnetz_new_state(cnetz, CNETZ_IDLE);
 	if (cnetz->dsp_mode == DSP_MODE_SPK_K || cnetz->dsp_mode == DSP_MODE_SPK_V) {
 		/* go idle after next frame/slot */
-		cnetz->sched_switch_mode = 1;
-		cnetz->sched_dsp_mode = (cnetz->sender.kanal == CNETZ_OGK_KANAL) ? DSP_MODE_OGK : DSP_MODE_OFF;
+		cnetz_set_sched_dsp_mode(cnetz, (cnetz->sender.kanal == CNETZ_OGK_KANAL) ? DSP_MODE_OGK : DSP_MODE_OFF, 1);
 	} else {
-		cnetz->sched_switch_mode = 0;
-		cnetz->dsp_mode = (cnetz->sender.kanal == CNETZ_OGK_KANAL) ? DSP_MODE_OGK : DSP_MODE_OFF;
+		cnetz_set_sched_dsp_mode(cnetz, (cnetz->sender.kanal == CNETZ_OGK_KANAL) ? DSP_MODE_OGK : DSP_MODE_OFF, 0);
+		cnetz_set_dsp_mode(cnetz, (cnetz->sender.kanal == CNETZ_OGK_KANAL) ? DSP_MODE_OGK : DSP_MODE_OFF);
 	}
 }
 
@@ -1014,8 +1011,7 @@ wbn:
 			telegramm.frequenz_nr = spk->sender.kanal;
 			cnetz_new_state(spk, CNETZ_BUSY);
 			/* schedule switching two slots ahead */
-			spk->sched_switch_mode = 2;
-			spk->sched_dsp_mode = DSP_MODE_SPK_K;
+			cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_SPK_K, 2);
 			unlink_transaction(trans);
 			link_transaction(trans, spk);
 			/* flush all other transactions, if any (in case of OgK/SpK) */
@@ -1251,8 +1247,7 @@ const telegramm_t *cnetz_transmit_telegramm_spk_k(cnetz_t *cnetz)
 			/* next sub frame */
 			trans_new_state(trans, TRANS_VHQ);
 			trans->count = 0;
-			cnetz->sched_switch_mode = 1;
-			cnetz->sched_dsp_mode = DSP_MODE_SPK_V;
+			cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_SPK_V, 1);
 #ifndef DEBUG_SPK
 			timer_start(&trans->timer, 0.075 + 0.6 * F_VHQ); /* one slot + F_VHQ frames */
 #endif
@@ -1269,8 +1264,7 @@ const telegramm_t *cnetz_transmit_telegramm_spk_k(cnetz_t *cnetz)
 			/* next sub frame */
 			trans_new_state(trans, TRANS_VHQ);
 			trans->count = 0;
-			cnetz->sched_switch_mode = 1;
-			cnetz->sched_dsp_mode = DSP_MODE_SPK_V;
+			cnetz_set_sched_dsp_mode(cnetz, DSP_MODE_SPK_V, 1);
 			timer_start(&trans->timer, 0.075 + 0.6 * F_VHQ); /* one slot + F_VHQ frames */
 		}
 		break;
diff --git a/src/cnetz/dsp.c b/src/cnetz/dsp.c
index 585a068..cca40dc 100644
--- a/src/cnetz/dsp.c
+++ b/src/cnetz/dsp.c
@@ -639,7 +639,7 @@ again:
 			if (--cnetz->sched_switch_mode == 0) {
 				/* OgK / SpK(K) / SpK(V) */
 				PDEBUG(DDSP, DEBUG_INFO, "Switching channel (mode)\n");
-				cnetz->dsp_mode = cnetz->sched_dsp_mode;
+				cnetz_set_dsp_mode(cnetz, cnetz->sched_dsp_mode);
 			}
 		}
 
@@ -827,3 +827,16 @@ void unshrink_speech(cnetz_t *cnetz, int16_t *speech_buffer, int count)
 	cnetz->sender.rxbuf_pos = pos;
 }
 
+void cnetz_set_dsp_mode(cnetz_t *cnetz, enum dsp_mode mode)
+{
+	PDEBUG(DDSP, DEBUG_DEBUG, "DSP mode %d -> %d\n", cnetz->dsp_mode, mode);
+	cnetz->dsp_mode = mode;
+}
+
+void cnetz_set_sched_dsp_mode(cnetz_t *cnetz, enum dsp_mode mode, int frames_ahead)
+{
+	PDEBUG(DDSP, DEBUG_DEBUG, "Schedule DSP mode %d -> %d in %d frames\n", cnetz->dsp_mode, mode, frames_ahead);
+	cnetz->sched_dsp_mode = mode;
+	cnetz->sched_switch_mode = frames_ahead;
+}
+
diff --git a/src/cnetz/dsp.h b/src/cnetz/dsp.h
index 63c8630..7e69b9e 100644
--- a/src/cnetz/dsp.h
+++ b/src/cnetz/dsp.h
@@ -4,4 +4,6 @@ int dsp_init_sender(cnetz_t *cnetz, int measure_speed, double clock_speed[2], do
 void dsp_cleanup_sender(cnetz_t *cnetz);
 void calc_clock_speed(cnetz_t *cnetz, uint64_t samples, int tx, int result);
 void unshrink_speech(cnetz_t *cnetz, int16_t *speech_buffer, int count);
+void cnetz_set_dsp_mode(cnetz_t *cnetz, enum dsp_mode mode);
+void cnetz_set_sched_dsp_mode(cnetz_t *cnetz, enum dsp_mode mode, int frames_ahead);
 
diff --git a/src/nmt/dsp.c b/src/nmt/dsp.c
index b66a2b0..3f18f0b 100644
--- a/src/nmt/dsp.c
+++ b/src/nmt/dsp.c
@@ -607,6 +607,8 @@ void nmt_set_dsp_mode(nmt_t *nmt, enum dsp_mode mode)
 	/* reset telegramm */
 	if (mode == DSP_MODE_FRAME && nmt->dsp_mode != mode)
 		nmt->frame = 0;
+
+	PDEBUG(DDSP, DEBUG_DEBUG, "DSP mode %d -> %d\n", nmt->dsp_mode, mode);
 	nmt->dsp_mode = mode;
 }