You need to send it twice: once to each serial port.

When you write to SBUF0 it will write to serial port 0, when you write to SBUF1 it will write to serial port 1 (I believe those are the names of the SFRs, it's been awhile since I've worked with the 80C320).

In 'C' you'd code the following to write the letter "A" to both serial ports:

SBUF0 = 'A';
SBUF1 = 'A';

Be sure to include the appropriate header file for the 80C320 since SBUF0 and SBUF1 are not standard 8051 SFRs.

Craig Steiner