I the following is code which i am using as second UART but I am not getting the output can anyone tell what could be wroung in the code

RxD1 EQU P3.6 ; reception pin
TxD1 EQU P3.7 ; transmission pin
SR_SPEED EQU 4 ; reception at 1200 bauds
ST_SPEED EQU 4 ; transmission at 1200 bauds

ST_READY BIT 1 ; 1 if transmitter ready
SR_READY BIT 1 ; 1 if receiver ready
SR_ERROR BIT 1 ; 1 if receiver error
SR_INCOM BIT 1 ; 1 if character received



SR_CH DATA 1 ; character in reception
SR_COUNT DATA 1 ; internal counter
SR_STATUS DATA 1 ; receiver status
SR_CHAR DATA 1 ; character received

ST_CHAR DATA 1 ; character in transmission
ST_COUNT DATA 1 ; internal counter
ST_STATUS DATA 1 ; transmitter status

org 0000H


AJMP MAIN

ORG 001BH

JMP SI_INTERRUPT
;*****************************************************************************
MAIN: ACALL SI_INSTALL ; serial interface installation
LOOP: ;ACALL SI_RXD ; wait for a character reception
MOV A,#'D'
ACALL SI_TXD ; send character received
SJMP LOOP

;******************************************************

SI_INSTALL: MOV TCON,#40H ; Timer 1 enabled
MOV TMOD,#20H ; 8-bit auto-relaod
MOV TH1,#0E8H ; 1200 bauds
MOV SCON,#52H ; serial port mode 1
SETB ST_READY ; transmitter ready
SETB SR_READY ; receiver ready
CLR SR_ERROR ; no error
SETB ET1 ; Timer 1
SETB EA
RET
;******************************************************

SI_TXD: JNB ST_READY,SI_TXD
mov R1,#st_ready
MOV C,P
MOV ACC.7,C ; set parity
MOV ST_CHAR,A ; character to send
MOV ST_COUNT,#(ST_SPEED/2) ; set counter at 1/2 bit duration
MOV ST_STATUS,#0 ; status initialization
CLR ST_READY ; start transmission
RET
;******************************************************

SI_RXD: JNB SR_INCOM,SI_RXD
MOV A,SR_CHAR ; character received
CLR SR_INCOM ; character readed
RET*/
;******************************************************

SI_INTERRUPT: JNB SR_READY,SR_INTL ; receiver not busy
JB RxD1,ST_INT0 ; start bit ?
CLR SR_READY
MOV SR_COUNT,#(SR_SPEED/2) ; load counter at 1/2 bit duration
MOV SR_STATUS,#0 ; status initialization
SJMP ST_INT0
SR_INTL: DJNZ SR_COUNT,ST_INT0 ; sample point ?
PUSH ACC
PUSH PSW
MOV A,SR_STATUS
JNZ SR_INT3
JB RxD1,SR_FRAME ; start bit OK (0) ?
SR_INT2: INC SR_STATUS
MOV SR_COUNT,#SR_SPEED
SJMP SR_INT5
SR_FRAME: SETB SR_READY
SETB SR_ERROR ; receiver error
SJMP SR_INT5
SR_INT3: CJNE A,#9,$+3 ; 8 bits + stop bit
JNC SR_INT4
MOV C,RxD1 ; bit sampling
MOV A,SR_CH
RRC A
MOV SR_CH,A
SJMP SR_INT2
SR_INT4: JNB RxD1,SR_FRAME ; stop bit OK (1) ?
MOV SR_CHAR,SR_CH ; save character received
SETB SR_READY
SETB SR_INCOM ; 1 char. received
SR_INT5: POP PSW
POP ACC
ST_INT0: ; transmission part
JB ST_READY,ST_INT5 ; exit if no character to send
DJNZ ST_COUNT,ST_INT5 ; sample point ?
PUSH ACC
PUSH PSW
MOV A,ST_STATUS
JNZ ST_INTL ; start ?
CLR TxD1 ; set start bit
MOV ST_COUNT,#ST_SPEED
INC ST_STATUS
SJMP ST_INT4
ST_INTL: CJNE A,#9,$+3 ; 8 bits + stop bit
JNC ST_INT2
MOV A,ST_CHAR
RRC A ; bit to send in carry
MOV ST_CHAR,A
MOV TxD1,C ; transmission of bit
MOV ST_COUNT,#ST_SPEED ; counter initialization
INC ST_STATUS
SJMP ST_INT4
ST_INT2: CJNE A,#10,ST_INT3 ; end of character ?
SETB ST_READY
SJMP ST_INT4
ST_INT3: SETB TxD1 ; set stop bit
MOV ST_COUNT,#ST_SPEED
INC ST_STATUS
ST_INT4: POP PSW
POP ACC
ST_INT5: RETI
END