Aside from Software Serial (Library) and the Serial that is meant to configure the unit (i.e: to burn the bootloader); my device (Arduino Nano) has 4 Serial Communication pins.
RX0/TX0 and RX1/TX1.
Considering Arduino allows only 1 Serial Communication (Hardware or Software Serial):
If I use the Hardware Serial Pins "0" pins; will I still be able to use Hardware Serial Pins "1" at the same time?
This A Single Arduino Uno with 14 RS-232 Ports may be useful for you