I have some time using Arduino and I have developed a project based on an Arduino Nano for a friend that monitors data and sends it over the Serial Monitor. The code has a test routine I put in the firmware when you send "marco" over the COM it returns "Polo". Let's call the project "Arduino 1" to ease things.
Later on, for testing purposes, I built a copy of the setup using another Arduino Nano with the exact same peripherals and firmware, which I used as a tester. Let's call this Arduino 2.
Both Arduino 1 and 2 work just fine on my PC. They were not plugged in at the same time in any PC as this doesn't make sense in this experiment. Each Arduino (1 and 2) works alone and separately as Arduino 2 was just for test purposes as I was developing a Java interface to read and display the data acquired from the COM port while Arduino 1 was with my friend.
After delivering the Arduino 1 to my friend, it doesn't work on his PC. So I took his PC home to run some tests. Let's call my PC as PC1 and my friend's PC as PC2 to ease things.
Arduino 2 works just fine on PC2. But Arduino 1 doesn't. It never returns the "Polo" when setting the correct COM ports.
And here's the tricky part: BOTH Arduino 1 and 2 work fine on PC1. But only Arduino 2 works on PC2. This is a problem once my goal is to have Arduino 1 working fine on PC2!
To make sure, I have installed the same version of Arduino IDE (1.8.13) from PC1 on PC2 and also the COM drivers, but so far I have no idea of what might be happening.
Another test I did was to take another Arduino (let's call it Arduino 3) and upload the same firmware. The bare Arduino 3 worked just fine on PC2. But when I replaced it on the Arduino 2 setup. It stopped communicating with PC2 as well, but still communicates with PC1!
Something in the setup might be preventing the Arduino 1 from working in PC2, but at the same time it's working properly on PC1. Any ideas?
The 3 arduino nanos are those Rev 3 afaik.
Thank you in advance!