I'm not sure if this is the right place to ask, but since you helped my so much in the past, I thought it's worth a try. So as I stated in my [last question](https://arduino.stackexchange.com/questions/71584/arduino-gps-simulator-softwareserial-issues), I'm using my Arduino Leonardo to simulate a GPS Receiver. The Arduino is now connected to a [Velodyne VLP-16 LiDAR](https://levelfivesupplies.com/product/velodyne-puck-vlp-16/) Here's what the Lidar needs: [![Requirements of the LiDAR][1]][1] I wired it like this: [![Schematic][2]][2] And wrote the following code: #include <SoftwareSerial.h> SoftwareSerial mySerial(7, 6); //232_TX,232_ int triggerFreq = 1; unsigned long timestamp; unsigned long triggerStartTime; const unsigned long dt = 1000000/triggerFreq; //micros unsigned long i; float gprmc = 181721.000; void setup() { pinMode(11, OUTPUT); // PPS pinMode(12, OUTPUT); // Indicator of msg_sent Serial.begin(9600); mySerial.begin(9600); triggerStartTime = micros(); } void loop() { timestamp = micros()-triggerStartTime; if (timestamp>= dt*i+200000) { digitalWrite(12,HIGH); i +=1; gprmc += 1; mySerial.print("$GPRMC,"); if (gprmc < 100000) mySerial.print(F("0")); mySerial.print(gprmc,3); mySerial.print(F(",A,4042.695,N,07400.796,W,,,080120,000.0,W*63")); Serial.print("$GPRMC,"); if (gprmc < 100000) Serial.print(F("0")); Serial.print(gprmc,3); Serial.print(F(",A,4042.695,N,07400.796,W,,,080120,000.0,W*63")); digitalWrite(12,LOW); } else if (timestamp>=dt*i+100000) { digitalWrite(11,LOW); } else if (timestamp>=dt*i) { digitalWrite(11,HIGH); } } Here's the situation now: - I'm seeing on the board that the messages are being sent (TX LED flashing) - I'm also seeing that the pulse is sent correctly (flashing LED) - I don't measure any voltage on the TX output pin (RS232 pin3) (I'm just using my multimeter, but normally it reacts to such short voltage pulses by blinking an LED) - I do measure such a pulse on RS232 pin4 - The LiDAR doesn't react to my sent messages Now my question: Do you see an error in my implementation? Is the message sent correctly? Thank you sooo much for your help! I'm really appreciating it! [1]: https://i.sstatic.net/QDpzP.png [2]: https://i.sstatic.net/d5XWS.png