CNVRT:   MOV    B, A
         SWAP   A
         ANL    A, #0FH
         ORL    A, #30H
         ACALL  SEND
         MOV    A, B
         ANL    A, #0FH
         ORL    A, #30H
         ACALL  SEND
         RET

SEND:    MOV    SBUF, A
H1:      JNB    TI, H1
         CLR    TI
         RET
         END