Thanks for pointing out the obvious. Sometimes I need that. For the the Uno, this seems to be the ATmega8U2/16U2 datasheet which states "If 9-bit characters are used (UCSZn = 7), the ninth bit must be written to the TXB8 bit in UCSRnB before the low byte of the character is written to UDRn." And for receive "the ninth bit must be read from the RXB8n bit in UCSRnB before reading the low bits from the UDRn." Just wanted I wanted to know. Thanks for the nudge in the right direction.