diff --git a/.gitignore b/.gitignore
index 94dab4e2..11c9c013 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+*.swp
 /*.user
 /build*
 .DS_Store
diff --git a/libsrc/leddevice/LedDeviceFactory.cpp b/libsrc/leddevice/LedDeviceFactory.cpp
index cb733a44..3257904e 100755
--- a/libsrc/leddevice/LedDeviceFactory.cpp
+++ b/libsrc/leddevice/LedDeviceFactory.cpp
@@ -284,7 +284,7 @@ LedDevice * LedDeviceFactory::construct(const Json::Value & deviceConfig)
 		{
 			device = new LedDeviceUdpE131(
 				deviceConfig["output"].asString(),
-				deviceConfig.get("latchtime",500000).asInt(),
+				deviceConfig.get("latchtime",104000).asInt(),
 				deviceConfig.get("universe",1).asInt()
 			);
 		}
diff --git a/libsrc/leddevice/LedDeviceUdpE131.cpp b/libsrc/leddevice/LedDeviceUdpE131.cpp
index dbd6744b..813a7382 100644
--- a/libsrc/leddevice/LedDeviceUdpE131.cpp
+++ b/libsrc/leddevice/LedDeviceUdpE131.cpp
@@ -23,52 +23,85 @@ LedDeviceUdpE131::LedDeviceUdpE131(const std::string& outputDevice, const unsign
 #define CID "hyperion!\0"
 #define SOURCE_NAME "hyperion on hostname\0"
 
-int LedDeviceUdpE131::write(const std::vector<ColorRgb> &ledValues)
+// populates the headers
+void LedDeviceUdpE131::prepare(const unsigned this_universe, const unsigned this_dmxChannelCount)
 {
-	_ledCount = ledValues.size();
-	int _dmxChannelCount = 3 * std::min(_ledCount,170);	// DMX512 has max 512 channels == 170 RGB leds
-
 	memset(e131_packet.raw, 0, sizeof(e131_packet.raw));
 
 	/* Root Layer */
 	e131_packet.preamble_size = htons(16);
 	e131_packet.postamble_size = 0;
 	memcpy (e131_packet.acn_id, _acn_id, 12);
-	e131_packet.root_flength = htons(0x7000 | (110+_dmxChannelCount) );
+	e131_packet.root_flength = htons(0x7000 | (110+this_dmxChannelCount) );
 	e131_packet.root_vector = htonl(VECTOR_ROOT_E131_DATA);
 	memcpy (e131_packet.cid, CID, sizeof(CID) );
 
 	/* Frame Layer */
-	e131_packet.frame_flength = htons(0x7000 | (88+_dmxChannelCount));
+	e131_packet.frame_flength = htons(0x7000 | (88+this_dmxChannelCount));
 	e131_packet.frame_vector = htonl(VECTOR_E131_DATA_PACKET);
 	memcpy (e131_packet.source_name, SOURCE_NAME, sizeof(SOURCE_NAME));
 	e131_packet.priority = 100;
 	e131_packet.reserved = htons(0);
-	e131_packet.sequence_number = _e131_seq++;
 	e131_packet.options = 0;	// Bit 7 =  Preview_Data
 					// Bit 6 =  Stream_Terminated
 					// Bit 5 = Force_Synchronization
-	e131_packet.universe = htons(_e131_universe);
-
+	e131_packet.universe = htons(this_universe);
 
 	/* DMX Layer */
-	e131_packet.dmp_flength = htons(0x7000 | (11+_dmxChannelCount));
+	e131_packet.dmp_flength = htons(0x7000 | (11+this_dmxChannelCount));
 	e131_packet.dmp_vector = VECTOR_DMP_SET_PROPERTY;
 	e131_packet.type = 0xa1;
 	e131_packet.first_address = htons(0);
 	e131_packet.address_increment = htons(1);
-	e131_packet.property_value_count = htons(1+_dmxChannelCount);
+	e131_packet.property_value_count = htons(1+this_dmxChannelCount);
 
-	int led_idx=0;
 	e131_packet.property_values[0] = 0;	// start code
-	for (int _dmxIdx=1; _dmxIdx <=  _dmxChannelCount; )
+}
+
+int LedDeviceUdpE131::write(const std::vector<ColorRgb> &ledValues)
+{
+	int retVal = 0;
+
+	int _thisChannelCount = 0;
+
+	_e131_seq++;
+
+	const uint8_t * rawdata = reinterpret_cast<const uint8_t *>(ledValues.data());
+
+	_ledCount = ledValues.size();
+
+	int _dmxChannelCount = 3 * _ledCount;
+
+	for (int rawIdx = 0; rawIdx < _dmxChannelCount; rawIdx++)
 	{
-		e131_packet.property_values[_dmxIdx++] = ledValues[led_idx].red;
-		e131_packet.property_values[_dmxIdx++] = ledValues[led_idx].green;
-		e131_packet.property_values[_dmxIdx++] = ledValues[led_idx].blue;
-		led_idx ++;
+		if (rawIdx % DMX_MAX == 0) // start of new packet
+		{
+			_thisChannelCount = (_dmxChannelCount - rawIdx < DMX_MAX) ? _dmxChannelCount % DMX_MAX : DMX_MAX;
+//			                     is this the last packet?         ?    ^^ last packet      : ^^ earlier packets
+
+			prepare(_e131_universe + rawIdx / DMX_MAX, _thisChannelCount);
+			e131_packet.sequence_number = _e131_seq;
+		}
+
+		e131_packet.property_values[1 + rawIdx%DMX_MAX] = rawdata[rawIdx];
+
+//     is this the      last byte of last packet    ||   last byte of other packets
+		if ( (rawIdx == _dmxChannelCount-1) || (rawIdx %DMX_MAX == DMX_MAX-1) )
+		{
+#undef e131debug
+#if e131debug
+			printf ( "send packet: rawidx %d dmxchannelcount %d universe: %d, packetsz %d\n"
+				, rawIdx
+				, _dmxChannelCount
+				, _e131_universe + rawIdx / DMX_MAX
+				, E131_DMP_DATA + 1 + _thisChannelCount
+				);
+#endif
+			retVal &= writeBytes(E131_DMP_DATA + 1 + _thisChannelCount, e131_packet.raw);
+		}
 	}
-	return writeBytes(E131_DMP_DATA + 1 + _dmxChannelCount, e131_packet.raw);
+
+	return retVal;
 }
 
 int LedDeviceUdpE131::switchOff()
diff --git a/libsrc/leddevice/LedDeviceUdpE131.h b/libsrc/leddevice/LedDeviceUdpE131.h
index 783cb76d..01a6c04f 100644
--- a/libsrc/leddevice/LedDeviceUdpE131.h
+++ b/libsrc/leddevice/LedDeviceUdpE131.h
@@ -91,7 +91,7 @@ typedef union {
 #define E131_E131_UNIVERSE_DISCOVERY_INTERVAL	10		// seconds
 #define E131_NETWORK_DATA_LOSS_TIMEOUT		2500		// milli econds
 #define E131_DISCOVERY_UNIVERSE			64214
-
+#define DMX_MAX					512		// 512 usable slots
 
 ///
 /// Implementation of the LedDevice interface for sending led colors via udp/E1.31 packets
@@ -121,6 +121,8 @@ public:
 	virtual int switchOff();
 
 private:
+	void prepare(const unsigned this_universe, const unsigned this_dmxChannelCount);
+
 	e131_packet_t e131_packet;
 	uint8_t	_e131_seq = 0;
 	uint8_t	_e131_universe = 1;