Chris:
It looks like, after I looked at a data sheet for your processor, the P87C552, that you cannot have different baud rates for TXD and RXD on this part. This is a case where a variant of the original 8052 was quite a bit different in its implementation of TIMER2 from the standard structure.

It seems to me that you are stuck with one baud rate unless your software and the system is flexible. If it is possible for you to ignore the data coming from RxD during times you want to transmit to the TxD then there is a solution for you. You can normally set the Timer 1 baud rate up for the RxD baud rate you want to use and receive data when it comes. Then when you are ready to send data out TxD you can re-program the Timer 1 baud rate generator to your desired TxD rate and proceed to send your data out. Remember to allow enough time for the last byte to fully transfer out of TxD which is beyond the time that the Serial output register shows empty. After the transmit it complete then reset the Timer 1 baud rate back to your receive rate and resume waiting for input.

Note that during the time you are transmitting you will have to specifically ignore incoming data if you have not disabled the receiver and the source is trying to send data. It is possible that the stuff coming to RxD during this time will look like input but due to wrong baud clock the received data will be garbage.

Good Luck
Mike Karas