My understanding is that attachInterrupt () uses the hardware interrupt.
Perhaps I don't I understand but...
If I use for example attachInterrupt (Interrupt, function, Change) in void setup() then it will run the function when the pin changes for that interupt. Interrupts are tied to 4 pins.
Instead of polling inthe program for data.
I have not seen any examples of NewSoftSerial using this aproach.
I'm I clear as mud...
The goal is to pass data through serial from two maybe thress Duem or Uno to Mega.
I like to use serial TX and RX.