>Vitaliy never heard of this Tx invert feature, and >that was my point, it's kind of a recent development. I have an impression from somewhere that this is a development that has occurred to deal with IRDA transmission modes. It allows direct drive of a power transistor to drive the transmitting LED, and handle the output from typical detectors without an additional buffer. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist