An ASCII break is not a character, but rather a level on the transmit line. The break is a SPACE (logic 0) on the transmit line for a set duration, longer than the time for a character. In my case, I need to send a break of 100 mS duration to 'wake-up' my piece of equipment so I can send other commands to it over the serial line. Sending a NULL (0x00) won't work, as this is a valid ASCII character.