TING,

There are some mistakes here.
First of all don't forget that body of subroutine must be end by RET instruction.
Second, when you call H_4 there is endless loop, and code loses the DPTR value.

Try this code, I have changed it a little bit. Of course, the algorithm is up to you
only.



ORG 0
JMP MAIN

ORG 13H
SETB P2.7 ;turn on LED
MOV DPTR, #MSG1 ;load pointer for message
CALL message ;stay in loop indefinitly

MOV DPTR, #MSG2 ;load pointer for message
CALL message

JNB INT1, REC3
CLR P2.7
MOV DPTR, #MSG3 ;load pointer for message
CALL message
RETI

MAIN:
CALL INIT_LCD
CALL INIT_SERIAL
MOV IE, #10000100B ;enable external INT1

message1:
MOV DPTR, #STANDBY ;load pointer for message
next:
CLR A
MOVC A, @A+DPTR ;get the character
JZ B_1 ;if last character get out
CALL TRANS ;otherwise call transfer
CALL DATA_DISPLAY ;dispaly on LCD
INC DPTR ;next one
JMP next ;stay in loop indefinitly

B_1:
CALL RECV ;wait for data from serial port
CALL DATA_DISPLAY ;display data on lcd
JMP message1 ;stay in loop indefinitly


INIT_LCD:
MOV A, #30H ;initialize. lcd 1 lines,5*7 matrix
ACALL COMMAND ;issue command
MOV A, #0EH ;lcd on, cursor on
ACALL COMMAND ;issue command
MOV A, #01H ;clear lcd command
ACALL COMMAND ;issue command
MOV A, #06H ;shift cursor rigth
ACALL COMMAND ;issue command
MOV A, #86H ;cursor: line 1, pos.6
ACALL COMMAND ;issue command
RET

INIT_SERIAL:
MOV TMOD, #20h ;timer 1, mode 2(auto-reload)
MOV TH1, #0FDh ;9600 baud rate
MOV SCON, #50h ;8-bit,1 stop, REN enabled
SETB TR1 ;start timer 1
RET

message:
CLR A
MOVC A, @A+DPTR ;get the character
JZ eomess ;if last character get out
ACALL TRANS ;otherwise call transfer
ACALL DATA_DISPLAY ;dispaly on LCD
INC DPTR ;next one
SJMP message ;stay in loop indefinitly
eomee: ret


;serial data transfer. ACC has the data
TRANS:
MOV SBUF, A ;load the data

TRANS1:
JNB TI, TRANS1 ;stay here until last bit gone
CLR TI ;get ready for next character
RET ;return to caller

RECV: ;receive data serially in ACC
JNB RI, RECV ;wait here for character
MOV A, SBUF ;save it in ACC
CLR RI ;get ready for next character
RET ;return to caller

COMMAND:
ACALL READY ;is lcd ready
MOV P1, A ;issue command code
CLR RS ;RS=0 for command
CLR RW ;R/W=0 to write to lcd
SETB CE ;E=1 for H to L pulse
CLR CE ;E=0, latch in
RET

DATA_DISPLAY:
ACALL READY ;is lcd ready?
MOV P1, A ;issue data
SETB RS ;RS=1 for data
CLR RW ;R/W=0 to write to lcd
SETB CE ;E=1 for H to L pulse
CLR CE ;E=0, latch in
RET

;receive data serially in ACC
READY:
SETB P1.7 ;make p1.7 input port
CLR RS ;RS=0 access command reg
SETB RW ;R/W=1 read command reg

;read command reg and check busy flag
READY1:
CLR CE ;E=1 for H to L pulse
SETB CE ;E=0 H to L pulse
JB P1.7,READY1 ;stay until busy flag=0
RET

STANDBY: DB "STANDBY", 0
MSG1: DB "START RECORD", 0
MSG2: DB "FISNISH PRESS BUTTON", 0
MSG3: DB "THANK YOU", 0

END