redirecting standard in and standard out with serial port

I want to be able to send two bytes to /dev/cua1 and then read back 16 bytes. I want to do this from the command line or a shell script.

I want to send a capital "O" followed by a carriage return to /dev/cua1 at a baud rate of 300bps, 8 data bits, no parity, and 2 stop bits.

I then want to read back 16 bytes from /dev/cua1 at 300bps, 7 data bits, even parity, and 2 stop bits.  

Note: the different data bits and parity between writing and reading.

I'm running Redhat linux 5.0.

Thanks.  (Sorry for the lack of points, that's all I have)