diff --git a/epan/dissectors/packet-rdm.c b/epan/dissectors/packet-rdm.c
index c0c427ac67..451231efab 100644
--- a/epan/dissectors/packet-rdm.c
+++ b/epan/dissectors/packet-rdm.c
@@ -52,6 +52,8 @@ void proto_reg_handoff_rdm(void);
 #define RDM_SC_RDM				0xCC
 #define RDM_SC_SUB_MESSAGE			0x01
 
+#define RDM_CC_COMMAND_RESPONSE_FLAG		0x01
+
 #define RDM_CC_DISCOVERY_COMMAND		0x10
 #define RDM_CC_DISCOVERY_COMMAND_RESPONSE	0x11
 #define RDM_CC_GET_COMMAND			0x20
@@ -571,7 +573,9 @@ static int hf_rdm_checksum = -1;
 static int hf_rdm_checksum_status = -1;
 static int hf_rdm_trailer = -1;
 
-static int hf_rdm_pd_nack_reason = -1;
+static int hf_rdm_pd_ack_timer_estimated_response_time = -1;
+static int hf_rdm_pd_ack_overflow_uid = -1;
+static int hf_rdm_pd_nack_reason_code = -1;
 
 static int hf_rdm_pd_device_label = -1;
 
@@ -705,20 +709,6 @@ rdm_checksum(tvbuff_t *tvb, guint length)
 	return sum;
 }
 
-static guint
-dissect_rdm_pd_nack_reason(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint8 len _U_)
-{
-	switch(cc) {
-	case RDM_CC_GET_COMMAND_RESPONSE:
-	case RDM_CC_SET_COMMAND_RESPONSE:
-		proto_tree_add_item(tree, hf_rdm_pd_nack_reason, tvb, offset, 2, ENC_BIG_ENDIAN);
-		offset +=  2;
-		break;
-	}
-
-	return offset;
-}
-
 static guint
 dissect_rdm_pd_queued_message(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint8 len _U_)
 {
@@ -1805,34 +1795,303 @@ dissect_rdm_pd_preset_playback(tvbuff_t *tvb, guint offset, proto_tree *tree, gu
 	return offset;
 }
 
+static guint
+dissect_rdm_mdb_param_data(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint16 param_id, guint8 pdl)
+{
+	switch(param_id) {
+	case RDM_PARAM_ID_SENSOR_VALUE:
+		offset = dissect_rdm_pd_sensor_value(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_QUEUED_MESSAGE:
+		offset = dissect_rdm_pd_queued_message(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DMX_START_ADDRESS:
+		offset = dissect_rdm_pd_dmx_start_address(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEVICE_INFO:
+		offset = dissect_rdm_pd_device_info(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEVICE_MODEL_DESCRIPTION:
+		offset = dissect_rdm_pd_device_model_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEVICE_LABEL:
+		offset = dissect_rdm_pd_device_label(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEVICE_HOURS:
+		offset = dissect_rdm_pd_device_hours(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LAMP_HOURS:
+		offset = dissect_rdm_pd_lamp_hours(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LAMP_STRIKES:
+		offset = dissect_rdm_pd_lamp_strikes(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SENSOR_DEFINITION:
+		offset = dissect_rdm_pd_sensor_definition(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_MANUFACTURER_LABEL:
+		offset = dissect_rdm_pd_manufacturer_label(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DISC_UNIQUE_BRANCH:
+		offset = dissect_rdm_pd_disc_unique_branch(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DISC_MUTE:
+		offset = dissect_rdm_pd_disc_mute(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DISC_UN_MUTE:
+		offset = dissect_rdm_pd_disc_un_mute(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PROXIED_DEVICES:
+		offset = dissect_rdm_pd_proxied_devices(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PROXIED_DEVICE_COUNT:
+		offset = dissect_rdm_pd_proxied_device_count(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_COMMS_STATUS:
+		offset = dissect_rdm_pd_comms_status(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_STATUS_MESSAGES:
+		offset = dissect_rdm_pd_status_messages(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_STATUS_ID_DESCRIPTION:
+		offset = dissect_rdm_pd_status_id_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_CLEAR_STATUS_ID:
+		offset = dissect_rdm_pd_clear_status_id(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SUB_DEVICE_STATUS_REPORT_THRESHOLD:
+		offset = dissect_rdm_pd_sub_device_status_report_threshold(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SUPPORTED_PARAMETERS:
+		offset = dissect_rdm_pd_supported_parameters(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PARAMETER_DESCRIPTION:
+		offset = dissect_rdm_pd_parameter_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PRODUCT_DETAIL_ID_LIST:
+		offset = dissect_rdm_pd_product_detail_id_list(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_FACTORY_DEFAULTS:
+		offset = dissect_rdm_pd_factory_defaults(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LANGUAGE_CAPABILITIES:
+		offset = dissect_rdm_pd_language_capabilities(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LANGUAGE:
+		offset = dissect_rdm_pd_language(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SOFTWARE_VERSION_LABEL:
+		offset = dissect_rdm_pd_software_version_label(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_BOOT_SOFTWARE_VERSION_ID:
+		offset = dissect_rdm_pd_boot_software_version_id(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_BOOT_SOFTWARE_VERSION_LABEL:
+		offset = dissect_rdm_pd_boot_software_version_label(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DMX_PERSONALITY:
+		offset = dissect_rdm_pd_dmx_personality(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DMX_PERSONALITY_DESCRIPTION:
+		offset = dissect_rdm_pd_dmx_personality_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SLOT_INFO:
+		offset = dissect_rdm_pd_slot_info(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SLOT_DESCRIPTION:
+		offset = dissect_rdm_pd_slot_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEFAULT_SLOT_VALUE:
+		offset = dissect_rdm_pd_slot_value(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_RECORD_SENSORS:
+		offset = dissect_rdm_pd_record_sensors(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LAMP_STATE:
+		offset = dissect_rdm_pd_lamp_state(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_LAMP_ON_MODE:
+		offset = dissect_rdm_pd_lamp_on_mode(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DEVICE_POWER_CYCLES:
+		offset = dissect_rdm_pd_device_power_cycles(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DISPLAY_INVERT:
+		offset = dissect_rdm_pd_display_invert(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_DISPLAY_LEVEL:
+		offset = dissect_rdm_pd_display_level(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PAN_INVERT:
+		offset = dissect_rdm_pd_pan_invert(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_TILT_INVERT:
+		offset = dissect_rdm_pd_tilt_invert(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PAN_TILT_SWAP:
+		offset = dissect_rdm_pd_pan_tilt_swap(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_REAL_TIME_CLOCK:
+		offset = dissect_rdm_pd_real_time_clock(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_IDENTIFY_DEVICE:
+		offset = dissect_rdm_pd_identify_device(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_RESET_DEVICE:
+		offset = dissect_rdm_pd_reset_device(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_POWER_STATE:
+		offset = dissect_rdm_pd_power_state(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PERFORM_SELFTEST:
+		offset = dissect_rdm_pd_perform_selftest(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_SELF_TEST_DESCRIPTION:
+		offset = dissect_rdm_pd_self_test_description(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_CAPTURE_PRESET:
+		offset = dissect_rdm_pd_capture_preset(tvb, offset, tree, cc, pdl);
+		break;
+
+	case RDM_PARAM_ID_PRESET_PLAYBACK:
+		offset = dissect_rdm_pd_preset_playback(tvb, offset, tree, cc, pdl);
+		break;
+
+	default:
+		proto_tree_add_item(tree, hf_rdm_parameter_data_raw, tvb,
+			offset, pdl, ENC_NA);
+		offset += pdl;
+		break;
+	}
+
+	return offset;
+}
+
+static guint
+dissect_rdm_pd_ack_overflow(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint16 param_id _U_, guint8 pdl)
+{
+	if (pdl > 0) {
+		int i;
+
+		switch(cc) {
+		case RDM_CC_GET_COMMAND_RESPONSE:
+		case RDM_CC_SET_COMMAND_RESPONSE:
+			for (i = 0; i < (pdl / 6); i++) {
+				proto_tree_add_item(tree, hf_rdm_pd_ack_overflow_uid, tvb,
+						offset, 6, ENC_NA);
+				offset += 6;
+			}
+			break;
+		}
+	}
+
+	return offset;
+}
+
+static guint
+dissect_rdm_pd_ack_timer(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint16 param_id _U_, guint8 pdl)
+{
+	if (pdl == 2) {
+		switch(cc) {
+		case RDM_CC_GET_COMMAND_RESPONSE:
+		case RDM_CC_SET_COMMAND_RESPONSE:
+			proto_tree_add_item(tree, hf_rdm_pd_ack_timer_estimated_response_time, tvb,
+				offset, 2, ENC_BIG_ENDIAN);
+			offset += 2;
+			break;
+		}
+	}
+	return offset;
+}
+
+static guint
+dissect_rdm_pd_nack_reason(tvbuff_t *tvb, guint offset, proto_tree *tree, guint8 cc, guint16 param_id _U_, guint8 pdl _U_)
+{
+	if (pdl == 2) {
+		switch(cc) {
+		case RDM_CC_GET_COMMAND_RESPONSE:
+		case RDM_CC_SET_COMMAND_RESPONSE:
+			proto_tree_add_item(tree, hf_rdm_pd_nack_reason_code, tvb,
+				offset, 2, ENC_BIG_ENDIAN);
+			offset += 2;
+			break;
+		}
+	}
+
+	return offset;
+}
+
 static guint
 dissect_rdm_mdb(tvbuff_t *tvb, guint offset, proto_tree *tree)
 {
-	guint8	    cc;
+	guint8      cc;
+	guint8      rt;
 	guint16	    param_id;
-	guint8	    response_type = 0x00;
 	guint8	    parameter_data_length;
 	proto_tree *hi,*si, *mdb_tree;
 
+	rt = tvb_get_guint8(tvb, offset);
 	cc = tvb_get_guint8(tvb, offset + 4);
 
-	switch (cc) {
-	case RDM_CC_DISCOVERY_COMMAND:
-	case RDM_CC_GET_COMMAND:
-	case RDM_CC_SET_COMMAND:
-		proto_tree_add_item(tree, hf_rdm_port_id, tvb,
-			offset, 1, ENC_BIG_ENDIAN);
-		offset += 1;
-		break;
-
-	case RDM_CC_DISCOVERY_COMMAND_RESPONSE:
-	case RDM_CC_GET_COMMAND_RESPONSE:
-	case RDM_CC_SET_COMMAND_RESPONSE:
-		response_type = tvb_get_guint8(tvb, offset);
+	if ((cc & RDM_CC_COMMAND_RESPONSE_FLAG) == RDM_CC_COMMAND_RESPONSE_FLAG) {
 		proto_tree_add_item(tree, hf_rdm_response_type, tvb,
-			offset, 1, ENC_BIG_ENDIAN);
-		offset += 1;
-		break;
+				offset, 1, ENC_BIG_ENDIAN);
+	        offset += 1;
+
+	} else {
+		proto_tree_add_item(tree, hf_rdm_port_id, tvb,
+		                offset, 1, ENC_BIG_ENDIAN);
+	        offset += 1;
 	}
 
 	proto_tree_add_item(tree, hf_rdm_message_count, tvb,
@@ -1847,7 +2106,6 @@ dissect_rdm_mdb(tvbuff_t *tvb, guint offset, proto_tree *tree)
 			offset, -1, ENC_NA);
 	mdb_tree = proto_item_add_subtree(hi,ett_rdm);
 
-
 	proto_tree_add_item(mdb_tree, hf_rdm_command_class, tvb,
 			offset, 1, ENC_BIG_ENDIAN);
 	offset += 1;
@@ -1864,230 +2122,30 @@ dissect_rdm_mdb(tvbuff_t *tvb, guint offset, proto_tree *tree)
 	proto_item_set_len( mdb_tree,  parameter_data_length + 4);
 
 	if (parameter_data_length > 0) {
+
 		hi = proto_tree_add_item(mdb_tree, hf_rdm_parameter_data, tvb,
 				offset, parameter_data_length, ENC_NA);
 		si = proto_item_add_subtree(hi,ett_rdm);
 
-		if (response_type == RDM_RESPONSE_TYPE_NACK_REASON) {
-			offset = dissect_rdm_pd_nack_reason(tvb, offset, si, cc, parameter_data_length);
+		if ((cc & RDM_CC_COMMAND_RESPONSE_FLAG) == RDM_CC_COMMAND_RESPONSE_FLAG) {
 
-		} else {
-
-			switch(param_id) {
-			case RDM_PARAM_ID_SENSOR_VALUE:
-				offset = dissect_rdm_pd_sensor_value(tvb, offset, si, cc, parameter_data_length);
+			switch(rt) {
+			case RDM_RESPONSE_TYPE_ACK:
+				offset = dissect_rdm_mdb_param_data(tvb, offset, si, cc, param_id, parameter_data_length);
 				break;
-
-			case RDM_PARAM_ID_QUEUED_MESSAGE:
-				offset = dissect_rdm_pd_queued_message(tvb, offset, si, cc, parameter_data_length);
+			case RDM_RESPONSE_TYPE_ACK_TIMER:
+				offset = dissect_rdm_pd_ack_timer(tvb, offset, si, cc, param_id, parameter_data_length);
 				break;
-
-			case RDM_PARAM_ID_DMX_START_ADDRESS:
-				offset = dissect_rdm_pd_dmx_start_address(tvb, offset, si, cc, parameter_data_length);
+			case RDM_RESPONSE_TYPE_NACK_REASON:
+				offset = dissect_rdm_pd_nack_reason(tvb, offset, si, cc, param_id, parameter_data_length);
 				break;
-
-			case RDM_PARAM_ID_DEVICE_INFO:
-				offset = dissect_rdm_pd_device_info(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DEVICE_MODEL_DESCRIPTION:
-				offset = dissect_rdm_pd_device_model_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DEVICE_LABEL:
-				offset = dissect_rdm_pd_device_label(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DEVICE_HOURS:
-				offset = dissect_rdm_pd_device_hours(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LAMP_HOURS:
-				offset = dissect_rdm_pd_lamp_hours(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LAMP_STRIKES:
-				offset = dissect_rdm_pd_lamp_strikes(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SENSOR_DEFINITION:
-				offset = dissect_rdm_pd_sensor_definition(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_MANUFACTURER_LABEL:
-				offset = dissect_rdm_pd_manufacturer_label(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DISC_UNIQUE_BRANCH:
-				offset = dissect_rdm_pd_disc_unique_branch(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DISC_MUTE:
-				offset = dissect_rdm_pd_disc_mute(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DISC_UN_MUTE:
-				offset = dissect_rdm_pd_disc_un_mute(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PROXIED_DEVICES:
-				offset = dissect_rdm_pd_proxied_devices(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PROXIED_DEVICE_COUNT:
-				offset = dissect_rdm_pd_proxied_device_count(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_COMMS_STATUS:
-				offset = dissect_rdm_pd_comms_status(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_STATUS_MESSAGES:
-				offset = dissect_rdm_pd_status_messages(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_STATUS_ID_DESCRIPTION:
-				offset = dissect_rdm_pd_status_id_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_CLEAR_STATUS_ID:
-				offset = dissect_rdm_pd_clear_status_id(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SUB_DEVICE_STATUS_REPORT_THRESHOLD:
-				offset = dissect_rdm_pd_sub_device_status_report_threshold(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SUPPORTED_PARAMETERS:
-				offset = dissect_rdm_pd_supported_parameters(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PARAMETER_DESCRIPTION:
-				offset = dissect_rdm_pd_parameter_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PRODUCT_DETAIL_ID_LIST:
-				offset = dissect_rdm_pd_product_detail_id_list(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_FACTORY_DEFAULTS:
-				offset = dissect_rdm_pd_factory_defaults(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LANGUAGE_CAPABILITIES:
-				offset = dissect_rdm_pd_language_capabilities(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LANGUAGE:
-				offset = dissect_rdm_pd_language(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SOFTWARE_VERSION_LABEL:
-				offset = dissect_rdm_pd_software_version_label(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_BOOT_SOFTWARE_VERSION_ID:
-				offset = dissect_rdm_pd_boot_software_version_id(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_BOOT_SOFTWARE_VERSION_LABEL:
-				offset = dissect_rdm_pd_boot_software_version_label(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DMX_PERSONALITY:
-				offset = dissect_rdm_pd_dmx_personality(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DMX_PERSONALITY_DESCRIPTION:
-				offset = dissect_rdm_pd_dmx_personality_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SLOT_INFO:
-				offset = dissect_rdm_pd_slot_info(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SLOT_DESCRIPTION:
-				offset = dissect_rdm_pd_slot_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DEFAULT_SLOT_VALUE:
-				offset = dissect_rdm_pd_slot_value(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_RECORD_SENSORS:
-				offset = dissect_rdm_pd_record_sensors(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LAMP_STATE:
-				offset = dissect_rdm_pd_lamp_state(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_LAMP_ON_MODE:
-				offset = dissect_rdm_pd_lamp_on_mode(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DEVICE_POWER_CYCLES:
-				offset = dissect_rdm_pd_device_power_cycles(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DISPLAY_INVERT:
-				offset = dissect_rdm_pd_display_invert(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_DISPLAY_LEVEL:
-				offset = dissect_rdm_pd_display_level(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PAN_INVERT:
-				offset = dissect_rdm_pd_pan_invert(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_TILT_INVERT:
-				offset = dissect_rdm_pd_tilt_invert(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PAN_TILT_SWAP:
-				offset = dissect_rdm_pd_pan_tilt_swap(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_REAL_TIME_CLOCK:
-				offset = dissect_rdm_pd_real_time_clock(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_IDENTIFY_DEVICE:
-				offset = dissect_rdm_pd_identify_device(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_RESET_DEVICE:
-				offset = dissect_rdm_pd_reset_device(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_POWER_STATE:
-				offset = dissect_rdm_pd_power_state(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PERFORM_SELFTEST:
-				offset = dissect_rdm_pd_perform_selftest(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_SELF_TEST_DESCRIPTION:
-				offset = dissect_rdm_pd_self_test_description(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_CAPTURE_PRESET:
-				offset = dissect_rdm_pd_capture_preset(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			case RDM_PARAM_ID_PRESET_PLAYBACK:
-				offset = dissect_rdm_pd_preset_playback(tvb, offset, si, cc, parameter_data_length);
-				break;
-
-			default:
-				proto_tree_add_item(si, hf_rdm_parameter_data_raw, tvb,
-					offset, parameter_data_length, ENC_NA);
-				offset += parameter_data_length;
+			case RDM_RESPONSE_TYPE_ACK_OVERFLOW:
+				offset = dissect_rdm_pd_ack_overflow(tvb, offset, si, cc, param_id, parameter_data_length);
 				break;
 			}
+
+		} else {
+			offset = dissect_rdm_mdb_param_data(tvb, offset, si, cc, param_id, parameter_data_length);
 		}
 	}
 
@@ -2257,8 +2315,18 @@ proto_register_rdm(void)
 				FT_BYTES, BASE_NONE, NULL, 0x0,
 				NULL, HFILL }},
 
-		{ &hf_rdm_pd_nack_reason,
-			{ "NACK Reason", "rdm.pd.nack_reason",
+		{ &hf_rdm_pd_ack_overflow_uid,
+			{ "UID", "rdm.pd.ack_overflow.uid",
+				FT_BYTES, BASE_NONE, NULL, 0x0,
+				NULL, HFILL }},
+
+		{ &hf_rdm_pd_ack_timer_estimated_response_time,
+			{ "Estimated Response Time", "rdm.pd.ack_timer.estimated_response_time",
+				FT_INT16, BASE_DEC, NULL, 0x0,
+				NULL, HFILL }},
+
+		{ &hf_rdm_pd_nack_reason_code,
+			{ "NACK Reason Code", "rdm.pd.nack_reason.code",
 				FT_UINT16, BASE_HEX, VALS(rdm_nr_vals), 0x0,
 				NULL, HFILL }},