Winding back to the start of this thread, if your INPUT voltage is too low for a PIC, and it has Comparators, configure it as an Amplifier... you can receive Serial at 9600 Baud at MILIVOLT levels and the Comparator will happilly reconstruct 0-5v (and Invert it or not at your choice) which can then be read by SERIN, DEBUGIN or by a USART. Who needs a MAX232 anyway. A Comparator will do it all for you.