[PCR-1000] How to detect SSTV, FAX, rtty, ax.25 and other "data signals" on the air?

[Fabio Pietrosanti (naif)]

I'm completelly a newbie with radio communication but i have a lot of
experience with networking and security systems.

How can i recognize when "on the air" there's some particular protocol of
communications?

Does exists some kind of "network analizer" that during then scan allow me to
recognize different protocol?

Please let me know :)

-naif