Hi Vinod,

Instead of finding out what is wrong with your code, i am giving the full code which works fine. Just check it out and find whats wrong as compared to yours. You just have to adjust for the TH1 and TL1 load values by altering the V24SPD equate statement.

============================================
; Tested OK with 89c51RD2 kit running with 12Mhz crystal.
; Just configure COM2 port in WIN Hyperterminal for 4800/8/N/1 and set it to Auto Detect.
; Works with all types of terminal emulation in Hyper Terminal. Only in ViewData type there is
; some extra characters at the end. But still message can be read.


V24SPD EQU 256-26 ; for 4800 Baud

ORG 0000H

V24SET: MOV PCON, #80H
MOV TMOD, #22H
MOV TH1, #V24SPD MOV TL1, #V24SPD
SETB TCON.6
MOV SCON, #052H
;------------------------------------------------------

MAIN: MOV R7, #5 ; To print message 5 times
NEXT: MOV DPTR, #MSG
LCALL STXT
LCALL CRLF
MOV R4, #10
MOV R5, #255
MOV R6, #255
DLYLUP: DJNZ R5, $
MOV R5, #255
DJNZ R6, DLYLUP
MOV R6, #255
DJNZ R4, DLYLUP
DJNZ R7, NEXT

SJMP $
;-------------------------------------------------------

STXT: NOP ; send text from program store at DPTR
MOV A, #0
MOVC A, @A+DPTR
JZ ETXT
LCALL SEND
INC DPTR
SJMP STXT
ETXT: RET


BLANK: MOV A, #' ' ; send BLANK
SJMP SEND

CRLF: MOV A, #13 ; send a Carriage Return + Line Feed
LCALL SEND
MOV A, #10
LCALL SEND
RET


SEND: JNB SCON.1, $ ; wait for previous character to go..
CLR SCON.1
MOV SBUF, A
RET

GETCHR: NOP
GETC1: JNB SCON.0, GETC1
CLR SCON.0
MOV A, SBUF
RET

BYTE: PUSH ACC ; send BYTE SWAP A
LCALL NIBBLE
POP ACC
NIBBLE: ANL A, #0FH
ADD A, #246
JC HEXOUT
ADD A, #58
SJMP SEND
HEXOUT: ADD A, #65
SJMP SEND


MSG: DB 'This is Serial link test , 4800, N, 1'

END