I want to learn how to send ASCII code from Raspberry Pi 3 to a serial device. Communication protocol of Serial device via RS232 (TX, RX pins). I was trying to connect from kermit as follows but I failed;

  set line /dev/ttyS0        
  set carrier-watch off     
  set speed 9600            
  set flow none          
  set parity none
  set stop-bits 1        
  connect