GSM SIM900 Serial Monitor doubts

Hello everyone, my name is Salvatore. I'm using arduino uno r3 with gsm shield (tinysine sim900). I tried different examples and everything works ok. The only thing that I think is strange is that in the serial monitor I find all the modem's answers, for example :

ATT: OK
RIC: AT

OK

DB:ELSE
ATT: OK
RIC: AT

OK

DB:ELSE
ATT: OK
RIC: AT

OK

DB:CORRECT BR
ATT: OK
RIC: AT

OK

....

Is it normal or I have to modify the sketch? Maybe I have to comment the "serialprint" into the libraries? In the internet examples are printed only the lines in the sketch, for example: Serial.println("Esempio ricezione sms");

Are you using the examples supplied with the IDE, intended for use with the official Arduino shield, which uses the Quectel M10 chip, with your SIM900 based shield?

No, I'm using the examples I found in the SIM900 libraries (by: Marco Martines). I have no problems, but when I read the people's blog, I can see only serial phrases coming from the sketch and not by sim900. For example:

Is there a variable to set for stopping serial printing by the sim900 libraries or what?

Can you not either examine any library documentation, the code itself, or contact the author for assistance?

On the other hand you could write to the shield directly using Software Serial and have absolute control over what it does.

Can you not either examine any library documentation, the code itself, or contact the author for assistance?

I have examined all the documentation but I see nothing. I preferred write directly on Arduino forum because many people use the same library.
Actually in the SIM900 libraries code I see commands for serial printing but I can't believe that people in their blogs have commented or removed this lines

On the other hand you could write to the shield directly using Software Serial and have absolute control over what it does.

Yes, I can , but I want to understand this little problem.

P.S. I apologize for my bad English