Copernicus II (GPS), data reading problems!

Note: I posted a similar topic in "project guidance", but I realize that this is a section more relevant to my problems (I hope!)

Hi! I have purchased a Trimble Copernicus II GPS unit and I am trying to read its data on the serial monitor with an Arduino Uno. The unit came soldered onto a board with leads for 5v RS-232 and 3.3v TTL level outputs. I have tried hooking up the TTL output lead to the Uno's RX pin, but the serial monitor did not output anything. I tried using the SoftwareSerial library with pin 10 receiving, but it made no difference. I used this code during my testing:

byte aa;
void setup()
{
  Serial.begin(4800);
  Serial.println("It works, so far"); 
}

void loop() 
{
  if (Serial.available()>0) // if there is data coming into the serial line
  {
    aa = Serial.read(); // get the byte of data
    Serial.print(byte(aa)); // send it to the serial monitor
  }
}

I don't understand why nothing is being outputted. The GPS unit warms up when I apply power, and I can see that it updates itself every second by reading the data leads with a voltmeter. Can I please have some help with this? Thank you!

FIXED:

This is odd. The device is rated for 5 - 14 volts, I applied around 12.75v via external battery pack, but nothing showed up on the serial monitor. When I tried powering the device through the Arduino's 5v pin, voila, it works :p. Does anyone know why this happened?

I looked at the GPS data sheet and it is rated for 2.7-3.3V. My guess is that the regulator on your eval board did not like the higher voltage that you were applying.