Different bitrate for serial TX and RX?

Regarding communications with the Arduino over serial port: Is it possible for the ATMega328 and "standard Arduino libraries" (or only small modifications) to receive data at a different (lower) speed compared to the transmit speed.

Application in mind: After some setup routine, the main loop would log data received over slow serial communication and forward it on a higher speed with a serial-to-bluetooth module.

No.

I don't see why you couldn't use Serial.begin(9600); until you received some data, then use Serial.end(); followed by Serial.begin(115200); to blast it out a burst faster, then Serial.end(); and go back to Serial.begin(9600); for a while.

halfdome: and forward it on a higher speed with a serial-to-bluetooth module.

If you are using SoftwareSerial to communicate with the Bluetooth module and hardware serial (pins 0 and 1) to communicate with your PC they can have totally different baud rates.

I think you need to describe what you want to do in more detail.

...R

CrossRoads: I don't see why you couldn't use Serial.begin(9600); until you received some data, then use Serial.end(); followed by Serial.begin(115200); to blast it out a burst faster, then Serial.end(); and go back to Serial.begin(9600); for a while.

What happens if more data arrives when it's set to 115200?

while ( Serial.available() )
{
  Serial.read();
}