what is the ASCII character "/o" ?

Question

One time I was coding in Arduino. I used the littleBits Arduino bit board. I typed:
Serial.println("HIGH/ON");
delay(1000);
Then I saw the "/" and the "O" colored baby blue. I knew this was ASCII,
but what was it?

So does anyone know their ASCII characters?
Can somebody help me with this?

Answer 1

\0 is the null character, it is used to terminate strings in C.
(thats with character '\' before character zero, for escape)

Answer 2

Hmm, never seen this, and you're sure it wasn't a \0 (with the number zero, not the letter o)?

Answer 3

Yeah, I made sure to type "/o", not "/0".