Hi i'm Anne, i'm working my first time with Arduino MEGA.
i want to send to arduino MEGA some data to the Serial1 port and then sow this data by "Monitor" with Serial port.
How can i sent with Matlab data to Rx1 port (Serial1)? Whic is the COM?
thx
Anne 
Unfortunately I don't quite understand what you are asking.
Obviously english is not your main language.
I am happy to help if you can try to explain a bit more what you are trying to do.
Do you want to send serial data from the arduino to matlab or from matlab to your arduino?
Mowcius