How do I control audio device from serial ?

I want to control a quadravox mp3 player by sending serial commands via its RS232 input. I have connected the tx and rx pins of the UNO (via a Max233 level shifter) to the RS232 input of the Quadravox. Not knowing a fat lot about serial communication I haven’t a clue how to send a serial string. All the tutorials I can find show me how to send serial data via the usb port to the serial monitor using commands like serial.print but none tell me how to send out data via the tx pin. I would be grateful for some pointers on how to find out more please.

If you want to send something other than a character string:

Serial.write(value); // where 'value' is an integer from 0 to 255

Excellent, thanks. I'll give that a try !