My test232.c program can be used instead of minicom.

It copies:
   all chars from stdin to /dev/ttyS0
   all chars from /dev/ttyS0 to stdout

Note: the program can be stopped w/ Ctrl-C;

Usage samples:

./test232
sends what you type to XSB and prints what comes from XSB; same as minicom

cat file | ./test232
sends file to XSB and prints what comes from XSB

./test232  | while true; do time read a; echo $a; done
useful for timing
let's say you execute the code:
....
print("\nStart\n");
...
... interesting code
...
print("Stop\n");
...

You'll see how much time does the interesting code take.