send info back and forth using arduino's serial

Hi everyone, this would be my first question so I apologize if its under the wrong category...

As the title would say I'd like to know if its possible to connect Tx to Rx and Rx to Tx between two arduinos and do the serial.event() to basically share information, the information is just a String object of known size. I know about the Wire.h library, believe me I do my homework and usually all my questions are already answered but this time I have so many doubts.

If indeed I can, as I have read one uC has to be the Slave and the other one the Master, does that mean information can only flow one way or is it possible to have some kind of serial like when you connect your arduino to the PC.

thanks in advance!

Most Arduinos have at least one hardware Serial port. By default this is used for the USB serial connection, but if you aren't using that you can use it to connect to some external device by making a connection to pins 0 and 1. If you cross-connect pins 0 and 1 on a pair of Arduinos (i.e. pin 0 on one connects to pin 1 on the other, and vice versa) then you can establish a bidirectional serial connection between them. Of course using the hardware serial port like this means it isn't also available for use by the USB serial connection.

If you want to use the USB serial connection and an external serial connection at the same time then you also have the option of using a SoftwareSerial port on other I/O pins. SoftwareSerial has some limitations compared to the hardware Serial port but does give you the capability to send and receive.

You can get bidirectional communication between two arduinos connecting the tx/rx on one arduino to the rx/tx on the other arduino, and connecting the two arduinos together. You also need a small signal diode in each tx and rx line with the band end of the diode connected to the tx pin.

Don't forget that wiring two arduinos together for any purpose requires that there also be a common ground wire run between them, unless they are being powered by the same voltage source.