newsoftserial question

excuse guys,, what is the right format for newsoftserial?? serial(rx,tx) or serial(tx,rx)?? thanks a lot.. and do i really need a voltage limiter when im interfacing with a gsm module with serial operating in 3.3 v such as sim 900d?? thanks in advance :)

From NewSoftSerial.h:

  NewSoftSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic = false);

what if im using this one? what is the rx and tx of the format??

//Serial Relay - Arduino will patch a
//serial link between the computer and the GPRS Shield
//at 19200 bps 8-N-1
//Computer is connected to Hardware UART
//GPRS Shield is connected to the Software UART

#include <NewSoftSerial.h>

NewSoftSerial mySerial(8, 9);

void setup()
{
mySerial.begin(19200); // the GPRS baud rate
Serial.begin(19200); // the GPRS baud rate
}

void loop()
{
if(Serial.available())
{
mySerial.print((unsigned char)Serial.read());
}
else if(mySerial.available())
{
Serial.print((unsigned char)mySerial.read());
}

}

it’s rx,tx so in your example

NewSoftSerial mySerial(8, 9);

8 is rx.

thanks a lot ^^,