As Peter points out, an error of 2-3% should be tolerable. If your clock frequency is 24.576 MHz, you can obtain an inaccuracy of 2.5% at 9600 baud, 1.25% at 4800 baud, and 0.625% at 2400 baud by setting the SMOD bit in the PCON register (PCON.7) and using an auto-reload value of -13 for 9600 baud, -27 for 4800 baud and -53 for 2400 baud. The ideal reload values would be -40/3, -80/3 and -160/3. Note: if your clock frequency is 23.9616 MHz, your target bauds can be obtained with reload values of -13, -26 and -52 exactly.