i've modified the ISR. i remove the code that isn't need. the ISR looks:

void puerto_serial_event() interrupt 4{
    if(TI==1){          //if transmition occurs
        TI=0;           //clears TI
    }

    if (RI==1){       //if reception occurs
        RI=0;           //clears RI
        if(RB8){
            SM2=0;      //data mode 2
        }
        else{
            if(ind_trama>4){
                ind_trama=0;
            }
            trama[ind_trama]=SBUF;
            ind_trama++;
            SM2=1;      //data mode 1
        }
    }
}

but still have problems. so, i'll try to be more clear, so lets start again.

1st i'm new with sdcc, at89c52 and all this world of mcu's programming. thanks for the patience that you'll have with me.

well, to the facs.

i have 2 at89c52. i'll like to send from one to the other 5 bytes (char). the transmiter i'll name master and the reciver i'll name slave.

the master send the information to the slave by serial port, the slave must recive the information and verifiy it. i have problems with the communication, it seems like the master isn't transmting the info.

i'm innitializing the serial port with:

    ES=0;                   //disable serial port interrupt
    TI=0;                   //clears TI
    SCON=0xF0;              //uart mode 3 (9 bit), REN=1
    TMOD=TMOD|0x20;         //Timer 1 mode 2
    TH1=0xFD;               //19200 Bds
    TL1=0xFD; 				//19200 Bds
    ES=1;                   //enable serial port interrupt
    TR1=1;                  //run Timer 1

and the ISR is at the top of this message.

thanks 4 the help.