Marty

thanks a lot for you cooperation, yes I would like to receive your files, the a51 files if possible.

Guys this is my code:
ORG 0000H ;vector reset
JMP INICIO

ORG 0040H
INICIO:
MOV SCON, #052H ;REN=1 y RI=0
MOV TMOD, #020H
MOV TH1, #0FDH ; 9600 XTAL
;11.0592 M
what about TL1, does it needs to be initialized

SETB TR1
SETB TI

MOV A,#021H
MOV SBUF,A
JNB TI,$ ;I use it but
;I do not
;understand it very well
CLR TI

The hardware is very strange. The TX goes to a
Hex inverting schmitt trigger (74HC14)and the RX too.
I need this hardware configuration because my software programmer runs perfect.
What do you think about it?
I could use a protoboard to re invert the TX and RX.
by the way how are voltage levels in the rs232 standard?

thanks a lot!