The /etc/ttydefs file (see ttydefs(4)) contains information used by the ttymon(1M) port monitor to set up the speed and terminal settings of a port. The Serial Manager uses the configured speed, number of data bits and parity setting to create a line-mode label which indexes the ttydefs file. ttymon uses this information to configure the port. See the stty(1) manual page for information on the default control codes used in the ttydefs file.