yet another issue.

SERIAL: JB TI,CLEAR 
MOV A,SBUF 
CLR RI

Okay, you looks at TI and if it is not set then you think that it is RI which generates the interrupt. Some vendors (like Atmel AT89S8252/S53 etc) define SPI interrupt to the same vector address as UART`s one. As result, it may be not UART but SPI which requires the interrupt. So be careful about it as well. Better use something like:

INT_UART:
	JB	RI,INT_UART_GET
	JB	TI,INT_UART_SEND
; oops, if we are here then it needs
; some framework to fix a malfunction,
; be placed here
	RETI

Regards,
Oleg