That was a masterpiece of uncommented code.

When working with numeric constants larger than MAX_INT, you should add proper suffixes on the constants.

Don't write 120000, do write 120000ul if you want to perform 32-bit unsigned arithemetic, or 120000l (or better 120000L) for a long signed constant.

A huge number of your constants are larger than 32767 without any suffix specifying unsigned or long or unsigned long.

And what is "condition 1", "condition 2", ...
Are they random frequency ranges, or do they mean something?

What does a function call:
frequency_calc ( a, b, c, d, e, f);
do? 6 one-character variables. How will anyone manage to keep track of their meaning? Even if they represent six parameters received on the serial port, they must somehow have a meaning.